                  FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


AARON SENNE; MICHAEL LIBERTO;              Nos. 17-16245
OLIVER ODLE; BRAD MCATEE; CRAIG                 17-16267
BENNIGSON; MATT LAWSON; KYLE                    17-16276
WOODRUFF; RYAN KIEL; KYLE
NICHOLSON; BRAD STONE; MATT                  D.C. No.
DALY; AARON MEADE; JUSTIN                 3:14-cv-00608-
MURRAY; JAKE KAHAULELIO; RYAN                  JCS
KHOURY; DUSTIN PEASE; JEFF
NADEAU; JON GASTON; BRANDON
HENDERSON; TIM PAHUTA; LEE                  OPINION
SMITH; JOSEPH NEWBY; RYAN
HUTSON; MATT FREVERT; ROBERTO
ORTIZ; WITER JIMENEZ; KRIS WATTS;
MITCH HILLIGOSS; DANIEL BRITT;
YADEL MARTI; HELDER VELAQUEZ;
JORGE JIMENEZ; JORGE MINYETY;
EDWIN MAYSONET; JOSE DIAZ; NICK
GIARRAPUTO; LAUREN GAGNIER;
LEONARD DAVIS; GASPAR SANTIAGO;
GRANT DUFF; OMAR AGUILAR; MARK
WAGNER; DAVID QUINOWSKI;
BRANDON PINCKNEY, Individually
and on Behalf of All Those Similarly
Situated; JAKE OPITZ; BRETT
NEWSOME,
                 Plaintiffs-Appellants,

                  v.
2       SENNE V. KANSAS CITY ROYALS BASEBALL


KANSAS CITY ROYALS BASEBALL
CORP.; MARLINS TEAMCO LLC; SAN
FRANCISCO BASEBALL ASSOCIATES,
LLC; OFFICE OF THE COMMISSIONER
OF BASEBALL, DBA Major League
Baseball, an unincorporated
association; ALLAN HUBER SELIG,
“BUD”; ANGELS BASEBALL LP; ST.
LOUIS CARDINALS, LLC; COLORADO
ROCKIES BASEBALL CLUB, LTD.;
CINCINNATI REDS, LLC; HOUSTON
BASEBALL PARTNERS LLC;
ATHLETICS INVESTMENT GROUP,
LLC; ROGERS BLUE JAYS BASEBALL
PARTNERSHIP; PADRES L.P.; SAN
DIEGO PADRES BASEBALL CLUB, L.P.;
MINNESOTA TWINS, LLC; DETROIT
TIGERS, INC.; LOS ANGELES
DODGERS LLC; STERLING METS L.P.;
AZPB L.P.; NEW YORK YANKEES
P’SHIP; RANGERS BASEBALL EXPRESS,
LLC; MILWAUKEE BREWERS
BASEBALL CLUB, INC.; CHICAGO
CUBS BASEBALL CLUB, LLC;
PITTSBURGH ASSOCIATES, LP;
BASEBALL CLUB OF SEATTLE, LLP;
LOS ANGELES DODGERS HOLDING
COMPANY LLC; RANGERS BASEBALL,
LLC,
                Defendants-Appellees.
          SENNE V. KANSAS CITY ROYALS BASEBALL                  3

        Appeals from the United States District Court
           for the Northern District of California
        Joseph C. Spero, Magistrate Judge, Presiding

            Argued and Submitted June 13, 2018
                 San Francisco, California

                    Filed August 16, 2019

        Before: Michael R. Murphy, * Richard A. Paez,
             and Sandra S. Ikuta, Circuit Judges.

                   Opinion by Judge Paez;
                   Dissent by Judge Ikuta




    *
      The Honorable Michael R. Murphy, United States Circuit Judge
for the U.S. Court of Appeals for the Tenth Circuit, sitting by
designation.
4        SENNE V. KANSAS CITY ROYALS BASEBALL

                          SUMMARY **


      Labor Law / Class and Collective Certification

    The panel affirmed in part and reversed in part the
district court’s orders certifying a class and a collective
action for wage-and-hour claims brought by minor league
baseball players under the Fair Labor Standards Act and
state law.

    The district court certified a California class under
Federal Rule of Civil Procedure 23(b)(3) but denied
certification for Arizona and Florida classes and for a Rule
23(b)(2) class. The district court also certified an FLSA
collective.

    The panel held that, as to the state law claims, California
choice-of-law rules applied. The panel held that under
Sullivan v. Oracle Corp., 254 P.3d 237 (Cal. 2011),
California law applied to the Rule 23(b)(3) California class.
The panel reversed the district court’s determination that
choice-of-law considerations defeated the predominance and
adequacy requirements for the proposed Arizona and Florida
Rule 23(b)(3) classes. Applying California’s three-step
governmental interest analysis for choice-of-law questions,
the panel concluded that Arizona law should apply to the
work performed in Arizona, and Florida law to the work
performed in Florida.

   The panel reversed the district court’s refusal to certify a
Rule 23(b)(2) class for unpaid work at defendants’ training

    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
         SENNE V. KANSAS CITY ROYALS BASEBALL                  5

facilities in Arizona and Florida on the basis that choice-of-
law issues undermined “cohesiveness” and therefore made
injunctive and declaratory relief inappropriate. The panel
concluded that the district court’s errors in its choice-of-law
analysis relating to the proposed Arizona and Florida Rule
23(b)(3) classes applied equally to its refusal to certify the
Rule 23(b)(2) class. The panel further held that the district
court erred in imposing a “cohesiveness” requirement for the
proposed Rule 23(b)(2) class. The panel remanded for the
district court to consider anew whether to certify the Rule
23(b)(2) class.

    The panel held that plaintiffs could meet the
predominance requirement for the proposed California,
Florida, and Arizona Rule 23(b)(3) classes through a
combination of representative evidence and application of
the “continuous workday” rule. The panel applied the Mt.
Clemens burden-shifting framework and the holding of
Tyson Foods v. Bouaphakeo, 136 S. Ct. 1036 (2016), that
representative evidence may be used at the class certification
stage and may be used to establish liability in addition to
damages. The panel explained that the continuous workday
rule presumes that once the beginning of the workday is
triggered, an employee performs compensable work
throughout the rest of the day until the employee completes
their last principal activity. Any activity that is “integral and
indispensable” to principal activities triggers the beginning
of the workday. As to the Arizona and Florida classes,
covering alleged minimum wage violations in the lack of any
pay for time spent participating in spring training, extended
spring training, and instructional leagues, the panel affirmed
the determination that the predominance requirement was
met. As to the California class, covering overtime and
minimum wage claims relating to work performed during the
championship season, the panel held that the district court
6       SENNE V. KANSAS CITY ROYALS BASEBALL

did not abuse its discretion in concluding that defendants’
uniform pay policy, the team schedules, and representative
evidence, including an expert survey known as the “Main
Survey,” established predominance. The panel held that the
district court was not required to “rigorously analyze” the
Main Survey, rather than evaluating its admissibility under
Daubert and its appropriateness for meeting class
certification requirements under Tyson.

    Affirming the district court’s certification of the FLSA
collective action, the panel applied the standard set forth in
Campbell v. City of L.A., 903 F.3d 1090 (9th Cir. 2018),
which postdated the district court’s ruling, and held that the
district court’s use of the ad hoc approach was harmless
error. The panel concluded that collective certification was
proper because plaintiffs shared similar issues of law or fact
material to the disposition of their FLSA claims and thus
were similarly situated.

    The panel affirmed the district court’s certification of the
California Rule 23(b)(3) class and the FLSA collective
action, reversed the district court’s refusal to certify Arizona
and Florida classes and a Rule 23(b)(2) class, and remanded
for further proceedings.

    Dissenting, Judge Ikuta wrote that the district court
correctly concluded that consideration of plaintiffs’ claims
on a classwide basis would be overwhelmed by
individualized choice-of-law inquiries. She wrote that the
majority’s rule, applying the law of the jurisdiction where
the work took place, was contrary to the court’s framework
for analyzing the intersection of class action and choice-of-
law issues, overlooked the complexity of California’s
choice-of-law rules, and created significant practical and
logistical problems.
        SENNE V. KANSAS CITY ROYALS BASEBALL             7

                       COUNSEL

Robert L. King (argued) and Garrett R. Broshuis, Korein
Tillery LLC, St. Louis, Missouri; Bruce L. Simon and
Benjamin E. Shiftan, Pearson Simon & Warshaw LLP, San
Francisco, California; Daniel L. Warshaw and Bobby Pouya,
Pearson Simon & Warshaw LLP, Sherman Oaks, California;
for Plaintiffs-Appellants.

Elise M. Bloom (argued), Adam M. Lupion, and Mark D.
Harris, Proskauer Rose LLP, New York, New York; John E.
Roberts, Proskauer Rose LLP, Boston, Massachusetts; for
Defendants-Apellees.

David C. Frederick and Jeffrey A. Love, Kellogg Hansen
Todd Figel & Frederick PLLC, Washington, D.C., for Amici
Curiae Professors Peter Hay and Patrick J. Borchers.

Allan Steyer and Donald Scott MacRae, Steyer Lowenthal
Boodrookas Alvarez & Smith LLP, San Francisco,
California, for Amici Curiae Professional Hockey Players
Assocation; Association of Minor League Umpires; Office
and Professional Employee’s International Union; and
United Steel, Paper and Forestry, Rubber, Manufacturing,
Energy, Allied and Industrial Service Workers International
Union.
8       SENNE V. KANSAS CITY ROYALS BASEBALL

                          OPINION

PAEZ, Circuit Judge:

    It is often said that baseball is America’s pastime. In this
case, current and former minor league baseball players
allege that the American tradition of baseball collides with a
tradition far less benign: the exploitation of workers. We are
tasked with deciding whether these minor league players
may properly bring their wage-and-hour claims on a
collective and classwide basis.

                      BACKGROUND

                               I.

    Most major professional sports in America have their
own “farm system” for developing talent: for the National
Basketball Association, it’s the G-League; for the National
Hockey League, it’s the American Hockey League; and for
Major League Baseball (MLB), it’s Minor League Baseball.
MLB and its thirty franchise teams rely heavily on this
extensive minor league system, which has nearly 200
affiliates across the country and employs approximately
6,000 minor league players. Nearly all MLB players begin
their careers in the minor leagues. Each minor league club
is associated with one of the thirty franchise MLB teams.

    The minor league system is governed by the Major
League Rules (MLRs), which dictate the terms of
employment and compensation for both minor and major
league players. Under the MLRs, all minor league players
are required to sign a seven-year Uniform Player Contract
(UPC). Ostensibly, players are required to sign the UPC for
“morale” and “to produce the similarity of conditions
necessary for keen competition.”
          SENNE V. KANSAS CITY ROYALS BASEBALL                            9

    The UPC “obligates Player[s] to perform professional
services on a calendar year basis, regardless of the fact that
salary payments are to be made only during the actual
championship playing season.” It describes its scope as
setting “the terms and conditions of employment during all
periods in which Player is employed by Club as a Minor
League Player.” Players are paid by the MLB franchise
affiliated with the minor league team for which they play.
Under the UPC, first-year players are paid a fixed salary of
$1,100 per month during the regular (“championship”)
season that runs from April through September. In addition
to their salaries during the championship season, some
players receive signing or performance-related bonuses and
college scholarships.

    Beginning in early March each year, the minor league
affiliates conduct spring training in Arizona and Florida;
every MLB franchise operates a minor league training
complex in one of these two states. The parties dispute
whether spring training is required, but the UPC strongly
indicates that it is mandatory. 1 Virtually all players are
unpaid during spring training.

    Spring training lasts approximately four weeks, until the
championship season begins in April. Some players attest
that spring training entails working seven days a week, with
no days off. During spring training, teams typically have

    1
      The UPC provides that “Player’s duties and obligations under [the
UPC] continue in full force and effect throughout the calendar year,
including Club’s championship playing season, Club’s training season,
Club’s exhibition games, Club’s instructional, post-season training or
winter league games, any official play-off series, any other official post-
season series in which Player shall be required to participate . . . and any
remaining portions of the calendar year.”
10      SENNE V. KANSAS CITY ROYALS BASEBALL

scheduled activities in the morning prior to playing games in
the afternoon. For example, a team spring training schedule
for one of the San Francisco Giants’ affiliates describes that
at 6:30 AM, there was an “Early Van for Treatment and
Early Work” 2; at 7:00 AM, the “Regular Van” departed; at
7:45 AM, the “Early Work” began; and then between 9:00
AM and 11:00 AM, the team would perform activities such
as “Stretch,” “Throwing Program,” and “Batting Practice.”
Lunch was to be at 11:00 AM, before a 12:10 PM bus to a
neighboring city for a 1:00 PM away game.

    At the conclusion of spring training in early April, some
players are assigned to minor league affiliates, and begin
playing games in the championship season. During the
championship season, minor league teams play games either
six or seven days per week. The championship season lasts
around five months, beginning in April and ending in
September. One of the regular season leagues within minor
league baseball is the California League, which—as the
name implies—plays games exclusively within California.

    Players who are not assigned to play for affiliates in the
championship season stay at the Arizona or Florida facilities
for “extended spring training.” Extended spring training
continues until June, and involves similar activities to spring
training. Although most players do not get paid during
extended spring training, as many as seven MLB clubs do
pay for work during extended spring training due to an
ambiguity in the MLRs over when players are permitted to
be paid.



   2
     The schedule instructed players to “CHECK [the] BOARD FOR
EARLY WORK.”
         SENNE V. KANSAS CITY ROYALS BASEBALL                      11

    After the championship season ends in September, some
players participate in the “instructional leagues,” which run
from approximately mid-September to mid-October. The
parties dispute whether participation in the instructional
leagues is mandatory for the players involved, although as
with spring training, the UPC strongly implies that
participation is required. Activities and schedules during the
instructional league are similar to spring training. And just
as with spring training, players are virtually never paid for
participation in the instructional league.

                                 II.

    Plaintiffs are forty-five current and former minor league
baseball players who bring claims under the federal Fair
Labor Standards Act (FLSA) and the wage-and-hour laws of
California, Arizona, and Florida against MLB, MLB
Commissioner Bud Selig, and a number 3 of MLB franchises.
Plaintiffs allege that defendants do not pay the players at all
during spring training, extended spring training, or the
instructional leagues. They further allege that because
players are “employees” and the activities the players
perform during those periods constitute compensable work,
defendants have unlawfully failed to pay them at least
minimum wage. And according to plaintiffs, while the
players are paid—albeit not much—during the
championship season, they routinely work overtime, for
which they are never compensated as a matter of policy.

   In May 2015, plaintiffs filed their Second Amended
Consolidated Class Action Complaint, which alleged wage-

    3
      Plaintiffs originally named all 30 MLB franchises as defendants,
but eight of the franchises were subsequently dismissed for lack of
personal jurisdiction.
12      SENNE V. KANSAS CITY ROYALS BASEBALL

and-hour claims under the laws of eight states and the FLSA;
plaintiffs also sought certification of a FLSA collective
action. The district court preliminarily certified the FLSA
collective in October 2015.          Notice was sent to
approximately 15,000 current and former minor league
players, of which more than 2,200 opted in.

    In 2016, defendants moved to decertify the FLSA
collective, while plaintiffs moved to certify a Rule 23(b)(2)
class as well as Rule 23(b)(3) classes under the laws of eight
states. The district court denied certification for all proposed
Rule 23(b)(3) classes, concluding that predominance was not
satisfied for two primary reasons. Senne v. Kansas City
Royals Baseball Corp., 315 F.R.D. 523, 572, 577–84 (N.D.
Cal. 2016). First, the court concluded that predominance
was defeated by the choice-of-law issues presented by the
proposed classes, given that (1) the winter off-season
training claims entailed work performed in dozens of
different states with no common schedule or situs; and
(2) the championship season claims involved frequent travel
between state lines for away games. Id. at 580–81. The
district court also determined that the inclusion of claims for
winter off-season work fatally undermined predominance, as
the court would be required to undertake an overwhelming
number of individualized inquiries to determine which
activities constituted compensable “work” and how much
time was spent doing “work.” Id. at 577–84. For similar
reasons, the court held that plaintiffs were not “similarly
situated” and therefore decertified the FLSA collective. Id.
at 585–86. The court also granted the defendants’ motion to
exclude an expert survey (the “Pilot Survey”) submitted by
plaintiffs, finding that its methodology and results did not
satisfy the requirements of Federal Rule of Evidence 702 and
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S.
579 (1993). Id. at 586–90. The court further refused to
         SENNE V. KANSAS CITY ROYALS BASEBALL                    13

certify the proposed Rule 23(b)(2) class, concluding that
because the plaintiffs were all former—rather than current—
players, they lacked standing to represent a (b)(2) class. Id.
at 584–85.

    Plaintiffs moved for reconsideration, narrowing their
proposed classes significantly in response to the concerns the
district court expressed in its initial certification order.
Plaintiffs requested Rule 23(b)(3) certification of an Arizona
class and a Florida class for work performed during spring
training, extended spring training, and the instructional
leagues in those states.         Plaintiffs also moved for
certification of a 23(b)(3) California class, covering players
who participated in the California League during the
championship season. Additionally, plaintiffs sought to
certify a reworked FLSA collective of players who
participated in the California League or in spring training,
extended spring training, and the instructional leagues. In
addition to the 23(b)(3) classes and FLSA collective,
plaintiffs requested certification of a Rule 23(b)(2)
injunctive relief class consisting of current minor league
players who participate in spring training, extended spring
training, or the instructional leagues in Florida or Arizona.
To cure the court’s earlier concerns about standing, four
current minor league players moved to intervene to represent
the proposed (b)(2) class.

   On reconsideration, plaintiffs argued that they could
meet Rule 23(b)(3)’s predominance requirement and
FLSA’s “similarly situated” requirement through a
combination of the use of representative evidence and
application of the so-called “continuous workday” rule. 4

    4
      As we shall explain, the continuous workday rule presumes that
once the beginning of the workday is triggered, an employee performs
14        SENNE V. KANSAS CITY ROYALS BASEBALL

Plaintiffs’ representative evidence took a variety of forms,
including an expert survey (the “Main Survey”), hundreds of
team schedules, payroll data, and testimony from both
players and league officials. The most controversial piece of
evidence was the Main Survey, which plaintiffs argued
served as representative evidence of hours worked,
particularly when used in concert with a continuous workday
theory.

    The Main Survey asked players to report the times they
“most often” arrived and departed from the ballpark or
training facility during the championship season, spring
training, extended spring training, and the instructional
leagues, and asked players to estimate how much time they
spent eating meals while at the ballpark. The survey did not,
however, ask players about the kinds of activities they
performed at the facilities, or how much time they spent
performing particular activities. Given these purported
shortcomings, defendants moved to exclude the Main
Survey, and further argued that even if the survey were
admissible under Daubert, it still could not be used to meet
the predominance and “similarly situated” requirements due
to its alleged flaws. The district court denied defendants’
motion to exclude the Main Survey, finding it admissible
under Daubert and concluding that defendants’ challenges
went “to the weight of the Survey and not its admissibility”
and were “better left to a jury to evaluate.” The district court
further concluded that the Main Survey could be used in
combination with other evidence—such as team schedules,
testimony, and payroll data—to meet Rule 23(b)(3)’s

compensable work throughout the rest of the day until the employee
completes their last principal activity or the last activity which is
“integral and indispensable” to the employee’s principal activities. IBP,
Inc. v. Alvarez, 546 U.S. 21, 28, 32–37 (2005).
        SENNE V. KANSAS CITY ROYALS BASEBALL              15

predominance      and   FLSA’s       “similarly    situated”
requirements, observing that certifying the classes and the
FLSA collective “will not preclude Defendants from
challenging the sufficiency of the Main Survey and
Plaintiffs’ damages model on summary judgment and/or at
trial.”

    Because it concluded that the predominance and
“similarly situated” requirements could be met with the use
of representative evidence and application of the continuous
workday rule, the district court recertified the narrowed
FLSA collective and certified a California (b)(3) class.
However, the district court denied certification for the
Arizona, Florida, and (b)(2) classes, holding that choice-of-
law concerns defeated predominance for the Arizona and
Florida classes and undermined “cohesiveness” for the
(b)(2) class.

    At defendants’ request, the district court certified the
FLSA collective certification order for interlocutory review
under 28 U.S.C. § 1292. Plaintiffs petitioned us for
permission to appeal the denial of certification for the
Arizona, Florida, and Rule 23(b)(2) classes, and defendants
likewise petitioned to appeal the certification of the
California class; we granted both petitions, consolidating
those cross-appeals with the FLSA collective appeal.

               STANDARD OF REVIEW

    We review for abuse of discretion the district court’s
class certification rulings, and review for clear error any
findings of fact the district court relied upon in its
certification order. Parsons v. Ryan, 754 F.3d 657, 673 (9th
Cir. 2014). A district court’s choice of law determinations,
however, are reviewed de novo. Mazza v. Am. Honda Motor
Co., 666 F.3d 581, 589 (9th Cir. 2012). A district court
16       SENNE V. KANSAS CITY ROYALS BASEBALL

abuses its discretion where it commits an error of law, relies
on an improper factor, omits a substantial factor, or engages
in a clear error of judgment in weighing the correct mix of
factors. Stockwell v. City & County of San Francisco, 749
F.3d 1107, 1113 (9th Cir. 2014) (citing Bateman v. Am.
Multi-Cinema, Inc., 623 F.3d 708, 712 (9th Cir. 2010)).
When we review a grant of class certification, “we accord
the district court noticeably more deference than when we
review a denial.” Abdullah v. U.S. Sec. Assocs., Inc., 731
F.3d 952, 956 (9th Cir. 2013) (quoting Wolin v. Jaguar Land
Rover N. Am., LLC, 617 F.3d 1168, 1171 (9th Cir. 2010)).

                          ANALYSIS

    To paraphrase the Chief Justice, these complex appeals
require us to call a great number of balls and strikes, as both
parties raise numerous challenges to the district court’s
certification order. For their part, plaintiffs challenge the
district court’s decision to deny certification for the Arizona
and Florida Rule 23(b)(3) classes and the Rule 23(b)(2) class
on the grounds that choice-of-law issues defeated the
predominance requirement for the Arizona and Florida
(b)(3) classes and also thwarted “cohesiveness” for the
proposed (b)(2) class. Defendants, on the other hand, contest
the district court’s certification of the California (b)(3) class,
arguing first that choice-of-law issues defeat both
predominance and adequacy, and second, that plaintiffs
cannot meet the predominance requirement through the use
of their proffered representative evidence: the Main Survey,
team schedules, payroll records, deposition testimony, and
declarations. Defendants further charge that the district
court erred in certifying the FLSA collective because
plaintiffs’ representative evidence does not show that the
collective members are “similarly situated.” Defendants
also contend that the district court erred by not “rigorously
         SENNE V. KANSAS CITY ROYALS BASEBALL                     17

analyzing” plaintiffs’ expert evidence at the class and
collective certification stage. We address each argument in
turn.

                                 I.

    Class certification is governed by Federal Rule of Civil
Procedure 23. As a threshold matter, a party seeking class
certification must satisfy the four requirements of Rule
23(a): (1) numerosity; (2) commonality; (3) typicality; and
(4) adequacy of representation. 5 “Class certification is
proper only if the trial court has concluded, after a ‘rigorous
analysis,’ that Rule 23(a) has been satisfied.” Parsons, 754
F.3d at 674 (quoting Wang v. Chinese Daily News, Inc., 737
F.3d 538, 542–43 (9th Cir. 2013)).

    In addition to the requirements of Rule 23(a), a proposed
class must also meet the requirements of one or more of the
“three different types of classes” set forth in Rule 23(b).
Leyva v. Medline Industries, Inc., 716 F.3d 510, 512 (9th Cir.
2013). Here, plaintiffs proposed classes under two of Rule
23(b)’s class types: Rule 23(b)(3) and 23(b)(2). A class may
be certified under Rule 23(b)(3) only if the district court
“finds that the questions of law or fact common to class
members predominate over any questions affecting only
individual members, and that a class action is superior to
other available methods for fairly and efficiently
adjudicating the controversy.” Fed. R. Civ. P. 23(b)(3). Of
these two requirements—predominance and superiority—
only predominance is at issue on appeal.                 “The
predominance inquiry focuses on ‘the relationship between

    5
       Of Rule 23(a)’s four requirements, defendants contest only
adequacy on appeal; their arguments pertaining to adequacy have to do
with choice-of-law issues.
18      SENNE V. KANSAS CITY ROYALS BASEBALL

the common and individual issues’ and ‘tests whether
proposed classes are sufficiently cohesive to warrant
adjudication by representation.’” Vinole v. Countrywide
Home Loans, Inc., 571 F.3d 935, 944 (9th Cir. 2009)
(quoting Hanlon v. Chrysler Corp., 150 F.3d 1011, 1022 (9th
Cir. 1998)). In determining whether the predominance
requirement is met, courts have a “duty to take a close look
at whether common questions predominate over individual
ones” to ensure that individual questions do not “overwhelm
questions common to the class.” Comcast Corp. v. Behrend,
569 U.S. 27, 34 (2013) (internal quotation marks and citation
omitted).

    Rule 23(b)(2), on the other hand, requires only that “the
party opposing the class ha[ve] acted or refused to act on
grounds that apply generally to the class, so that final
injunctive relief or corresponding declaratory relief is
appropriate respecting the class as a whole.” Fed. R. Civ. P.
23(b)(2). Although 23(b)(2) classes are most common in the
civil rights context, “we have certified many different kinds
of Rule 23(b)(2) classes.” Parsons, 754 F.3d at 686.

                             II.

    We first address whether choice-of-law issues fatally
undermine plaintiffs’ proposed Rule 23 classes. The district
court’s decision was split on the impact of choice-of-law
questions: as to the proposed Rule 23(b)(3) California class,
the court held that choice-of-law concerns defeated neither
Rule 23(b)(3)’s predominance requirement nor Rule 23(a)’s
adequacy requirement. Yet as to the proposed 23(b)(3)
Arizona and Florida classes, the district court held the
opposite: that choice-of-law issues posed an insurmountable
hurdle to meeting both predominance and adequacy.
Similarly, the court determined that choice-of-law questions
        SENNE V. KANSAS CITY ROYALS BASEBALL               19

made certification of the proposed Rule 23(b)(2) class
inappropriate.

    Concerns over which state’s laws apply to a proposed
class “do not necessarily preclude a 23(b)(3) action.”
Hanlon, 150 F.3d at 1022. But “[u]nderstanding which law
will apply before making a predominance determination is
important when there are variations in applicable state law,”
and potentially varying state laws may defeat predominance
in certain circumstances. Zinser v. Accufix Research Inst.,
Inc., 253 F.3d 1180, 1189 (9th Cir. 2001) opinion amended
on denial of reh’g, 273 F.3d 1266 (9th Cir. 2001). We have
been particularly concerned about the impact of choice-of-
law inquiries in nationwide consumer class actions and
products liability cases. See, e.g., Mazza, 666 F.3d at 585,
591–94; Zinser, 253 F.3d at 1184–90.

     A district court considering state law claims brought in
federal court must utilize the choice-of-law rules of the
forum state—here, California. Klaxon Co. v. Stentor
Electric Mfg. Co., 313 U.S. 487, 496–97 (1941). “By
default, California courts apply California law unless a party
litigant timely invokes the law of a foreign state, in which
case it is the foreign law proponent who must shoulder the
burden of demonstrating that foreign law, rather than
California law, should apply to class claims.” In re Hyundai
& Kia Fuel Econ. Litig., 926 F.3d 539, 561 (9th Cir. 2019)
(en banc) (internal quotation marks and citations omitted).
To meet their burden, the objectors must satisfy California’s
three-step governmental interest test, used to resolve choice
of law issues. Id.

       First, the court determines whether the
       relevant law of each of the potentially
       affected jurisdictions with regard to the
       particular issue in question is the same or
20      SENNE V. KANSAS CITY ROYALS BASEBALL

       different. Second, if there is a difference, the
       court examines each jurisdiction’s interest in
       the application of its own law under the
       circumstances of the particular case to
       determine whether a true conflict exists.
       Third, if the court finds that there is a true
       conflict, it carefully evaluates and compares
       the nature and strength of the interest of each
       jurisdiction in the application of its own law
       to determine which state’s interest would be
       more impaired if its policy were subordinated
       to the policy of the other state, and then
       ultimately applies the law of the state whose
       interest would be the more impaired if its law
       were not applied.

Kearney v. Salomon Smith Barney, Inc., 137 P.3d 914, 922
(Cal. 2006) (internal quotation marks and citations omitted);
see also Hairu Chen v. Los Angeles Truck Centers, LLC, No.
S240245, 2019 WL 3281346, at *3 (Cal. July 22, 2019).

    In making its choice-of-law determinations, the district
court relied heavily on the California Supreme Court’s
decision in Sullivan v. Oracle Corp., 254 P.3d 237 (Cal.
2011), and the parties do not dispute that Sullivan provides
the most helpful guidance for the choice-of-law questions
before us. In Sullivan, the California Supreme Court
answered a certified question from this court regarding
whether California overtime law applied to non-resident
employees of a California corporation who worked primarily
in their home states of Colorado and Arizona, but also
worked in California (and several other states) for “entire
days or weeks” at a time. Id. at 239, 243. Sullivan first
concluded that as a matter of statutory construction,
California law applied to all work performed for days or
        SENNE V. KANSAS CITY ROYALS BASEBALL                 21

weeks at a time within the state’s borders, regardless of
whether it was performed by residents or non-residents. Id.
at 241–43. Next, Sullivan undertook California’s three-step
governmental interest analysis for choice-of-law questions.
Id. at 244–47. At the first step of the analysis—whether the
relevant laws differed—the court noted that California’s
overtime law “clearly” differed from the laws of the
plaintiffs’ home states. Id. at 245.

    At the second step—whether a “true” conflict existed—
the court held that the existence of a true conflict was
“doubtful, at best.” Id. The court explained that the second
step involves examining “each jurisdiction’s interest in the
application of its own law under the circumstances of the
particular case,” noting that a court “may make [its] own
determination of the relevant policies and interests, without
taking ‘evidence’ as such on the matter.” Id. (internal
quotation marks, alterations, and citations omitted). Sullivan
observed that “California has, and has unambiguously
asserted, a strong interest in applying its overtime law to all
nonexempt workers, and all work performed, within its
borders.” Id. at 245. The court concluded that “neither
Colorado nor Arizona has a legitimate interest in shielding
Oracle from the requirements of California wage law as to
work performed here.” Id. at 246.

    In so holding, the court rejected two specific arguments
advanced by Oracle. First, Oracle contended that because
Arizona and Colorado have workers’ compensation statutes
with express extraterritorial application, those statutes
indicate an interest in extending the protection of their
employment laws to their residents working outside the
state. Id. Not so, Sullivan held. While “a state has such an
interest, at least in the abstract, when the traveling, resident
employee of a domestic employer would otherwise be left
22      SENNE V. KANSAS CITY ROYALS BASEBALL

without the protection of another state’s law,” the states had
“expressed no interest in disabling their residents from
receiving the full protection of California overtime law when
working here, or in requiring their residents to work side-by-
side with California residents in California for lower pay.”
Id.

    Second, Oracle argued that Arizona and Colorado “have
an interest in providing hospitable regulatory environments
for their own businesses” and thus “also have an interest in
shielding their own businesses from more costly and
burdensome regulatory environments in other states.” Id.
Relying on principles of federalism, Sullivan dismissed this
argument. While “a state can properly choose to create a
business-friendly environment within its own boundaries,”
the federal Constitution does not require a state to substitute
“‘the conflicting statute of another state’” for its own laws
that are “‘applicable to persons and events’” within that
state. Id. (quoting Phillips Petrol. Co. v. Shutts, 472 U.S.
797, 822 (1985)). Nor does the Constitution “permit one
state to project its regulatory regime into the jurisdiction of
another state.” Id. (citing Healy v. Beer Insti., Inc., 491 U.S.
324, 336–37 (1989)).

     Finally, although Sullivan held that there was almost
certainly no true conflict because neither Arizona nor
Colorado had a “legitimate interest” in blocking the
application of California law to the work performed in
California, the court nonetheless proceeded to the third step
of the analysis “for the sake of argument.” Id. at 246–47.
Sullivan concluded that the analysis at the third step—
determining which state’s interest would be more impaired
if its policy were subordinated to the policy of the other
state—yielded a straightforward answer:
        SENNE V. KANSAS CITY ROYALS BASEBALL               23

       [T]o subordinate California’s interests to
       those     of     Colorado      and    Arizona
       unquestionably would bring about the greater
       impairment. To permit nonresidents to work
       in California without the protection of our
       overtime law would completely sacrifice, as
       to those employees, the state’s important
       public policy goals of protecting health and
       safety and preventing the evils associated
       with overwork. Not to apply California law
       would also encourage employers to substitute
       lower paid temporary employees from other
       states for California employees, thus
       threatening California’s legitimate interest in
       expanding the job market. By way of
       comparison, not to apply the overtime laws of
       Colorado and Arizona would impact those
       states’ interests negligibly, or not at all . . .
       Alternatively, viewing Colorado’s and
       Arizona's overtime regimens as expressions
       of a general interest in providing hospitable
       regulatory environments to businesses within
       their own boundaries, that interest is not
       perceptibly impaired by requiring a
       California employer to comply with
       California overtime law for work performed
       here.

Id. at 247 (citations omitted) (emphasis added).

                              A.

   We first conclude that the district court did not err in
holding that under Sullivan, California law should apply to
24        SENNE V. KANSAS CITY ROYALS BASEBALL

the (b)(3) California class. 6 Although defendants correctly
point out that Sullivan is not precisely analogous to the case
at hand, the two principal differences on which defendants
rely are unpersuasive. Specifically, defendants first rely on
the fact that while Sullivan involved a California
corporation, “most of the MLB Club Defendants with
affiliates in the California League are located outside
California.” But a close reading of Sullivan indicates that
California law should apply to the California class, even
though many of the employers are not headquartered in
California. For example, Sullivan expressly contemplated
that California’s overtime laws may not apply to non-
resident employees of an out-of-state business who enter
California only “temporarily during the course of a
workday,” but contrasted such a scenario with employees
who work in California for “entire days and weeks,” who are
covered by California law. Id. at 243 (emphases, internal
quotation marks, and citations omitted).

    Similarly, Sullivan specifically left open the possibility
that other California employment laws, such as pay stub
requirements, may not apply to non-resident employees of
out-of-state employers—with the clear implication that
overtime laws would apply to such employees. See id. at
243–44. Likewise, far from limiting its holding only to non-
resident employees of in-state employers, Sullivan merely
emphasized that employees of in-state employers would
especially be covered by California law. See id. at 243.

     6
       Contrary to the dissent’s criticism, Dissent at 74, we do not
shortcut the governmental interest analysis. As we explain in the text,
we believe that Sullivan mandates application of California law to the
California class. Rather than repeating Sullivan’s choice of law analysis,
we focus on several additional considerations that further support our
decision to affirm the district court’s reliance on Sullivan.
        SENNE V. KANSAS CITY ROYALS BASEBALL                25

      Second, defendants characterize Sullivan as resting on
the court’s determination that “neither Arizona nor Colorado
. . . has asserted an interest in regulating overtime work
performed in other states.” Defendants argue that here, by
contrast, “numerous” states have a competing interest in
regulating work performed in California. But defendants
misread Sullivan by erroneously presuming that its
conclusion at the third step—that subordinating
“California’s interests to those of Colorado and Arizona
unquestionably would bring about the greater
impairment”—hinged entirely on whether Arizona or
Colorado law had asserted an interest in extraterritorial
application of their wage laws. Id. at 247. It is certainly
accurate to say that Sullivan’s holding was influenced by the
fact that neither Arizona nor Colorado law purported to
apply extraterritorially. Yet the court’s discussion at step
three cannot fairly be read to support the argument that
California’s “strong interest in applying its overtime law to
. . . all work performed within its borders,” id. at 245, would
suddenly become the lesser-impaired interest in the event
another state expressed a clear interest in applying its wage
laws to work performed in California. Rather, Sullivan
strongly indicates that California’s interest in applying its
laws to work performed within its borders for days or weeks
at a time would reign supreme regardless of whether another
state expressed an interest in applying its own wage laws
instead of California’s.
26        SENNE V. KANSAS CITY ROYALS BASEBALL

   Although we read Sullivan as clearly mandating the
application of California law to the California class, two
additional considerations support our conclusion today. 7

    First, because the district court found that plaintiffs had
met their burden of showing that California law could
constitutionally be applied—a determination defendants do
not contest on appeal—the burden shifted to defendants “to
demonstrate ‘that foreign law, rather than California law,
should apply to class claims.’” Mazza, 666 F.3d at 590
(quoting Wash. Mut. Bank v. Superior Court, 15 P.3d 1071,
1081 (Cal. 2001)). The district court held that defendants
failed to meet this burden, because they had “not gone
beyond speculating in a general manner that the claims of
some members of the putative California Class might be
subject to the law of another state and that the interests of
another state might be more impaired by application of
California law.”

    Defendants specifically point to one of the named
plaintiffs—Mitch Hilligoss—as an example of the alleged
“need to conduct choice of law inquiries as to every member
of the California class.” The district court found this
example unpersuasive for several reasons, and we agree.
The defendants argued that Illinois law should apply to
Hilligoss’ work in California because the time he spent in
California was a small proportion of his overall career
(around two months out of a six-year career). The district
court, however, correctly read Sullivan as indicating that
California law should nonetheless apply to Hilligoss’
California work. Indeed, the proportion of time the non-

     7
      Moreover, as the dissent acknowledges, the California Supreme
Court has expressed a strong interest in regulating wage and hour claims
within its borders. Dissent at 77.
        SENNE V. KANSAS CITY ROYALS BASEBALL                27

resident employees in Sullivan worked in California was
quite small (and in one case, even less than the proportion of
Hilligoss’ career spent in California): during the relevant
three-year period, one worked 20 days, another 74 days, and
the third 110 days. 254 P.3d at 239. Put differently, the
employees in Sullivan worked in California approximately
1.8%, 6.7%, and 10% of the time, respectively. Id. What
mattered in Sullivan—and what matters here—is that when
the employees worked in California, they did so for “entire
days or weeks” at a time. Id. at 243.

    Second, practical considerations strongly support
applying California law to work performed in California, at
least as a general rule; to hold otherwise “would lead to
bizarre and untenable results.” See Brief for Professors Peter
Hay and Patrick J. Borchers, Dkt. No. 21, at 12–13
(hereinafter “Professors’ Amicus Brief”). If the law of the
state in which work is performed is not the law that generally
applies, employers and employees alike would be subjected
to an unworkable scheme. Employers would be required to
properly ascertain the residency status—itself not
necessarily an easy task, as any student or seasonal worker
could attest—of each of its employees. For every non-
resident employee, employers would then have to determine
whether the wage laws of that employee’s state of residence
apply extraterritorially, and then come up with different rules
for each of its employees according to their state of residence
and any extraterritorial application of their home state’s
laws. This would mean that at a single worksite, employees
working side-by-side in the same position would not only be
owed vastly different minimum wages, but also that an
employer would need to set different rules for meal and rest
breaks for different employees, and so on and so forth. It
cannot be in any state’s legitimate “interest” to foist such an
28        SENNE V. KANSAS CITY ROYALS BASEBALL

administrative nightmare upon both employers and
employees.

    Such a scenario would also result in an enormous
competitive advantage—or disadvantage—for prospective
employees based solely on their state of residency.
Employers would be incentivized to hire residents of states
with low minimum wages and otherwise employer-friendly
wage laws, while residents of states with higher minimum
wages and more protective employment laws would
suddenly be far less appealing. Amici Professors Hays and
Borchers persuasively point out that as defendants would
have it, a college student still domiciled in Seattle while
attending a Nebraska university would have to be paid $15
per hour at a part-time job in Nebraska, “nearly double
Nebraska’s minimum wage of $8 per hour.” Professors’
Amicus Brief at 13. This, of course, would put the student
at a crushing disadvantage; what rational employer would
hire her?

    Moreover, given the administrative cost involved in
attempting to comply with a patchwork of multiple states’
wage laws at a single workplace, some employers might
instead choose to stick to hiring only resident employees, or
perhaps only non-resident employees from a particular state
(presumably one with a low minimum wage and minimally
protective employment laws). 8



     8
      The California class consisted of those players who participated in
the California League, which plays games exclusively within California
during the championship season. The Arizona and Florida classes
consisted of those who performed during spring training, extended
spring training, and the instructional leagues in those states. Thus, the
dissent’s fear that employers will be required to research applicable state
         SENNE V. KANSAS CITY ROYALS BASEBALL                       29

    We do not foreclose the possibility that there could be
some circumstances in which a proper application of
California’s choice-of-law rules might lead to the
application of another state’s wage and hour laws to work
performed in California. Nor do we create a per se rule or
an unrebuttable presumption. We hold only that, given the
above considerations, we are more than satisfied that the
district court did not err in concluding that under Sullivan,
California law applies to the California class.

                                  B.

    We next address whether the district court erred in
determining that choice-of-law considerations defeated
predominance and adequacy for the proposed Arizona and
Florida Rule 23(b)(3) classes, and conclude that the district
court’s determination must be reversed. Our conclusion is
animated in part by several of the considerations outlined
above, which apply with equal force to the Arizona and
Florida classes. Moreover, the aforementioned enormous
practical implications of a contrary holding would be just as
problematic and unworkable in Arizona and Florida as in
California.

                                  1.

     With those considerations in mind, we apply California’s
three-step governmental interest analysis, and conclude that
Arizona law should apply to the work performed in Arizona,
and Florida law to the work performed in Florida. At the
first step, we agree with defendants that the differences in
state law are “material,” meaning that “they make a

laws whenever an employee crosses state lines is overstated. Dissent at
84.
30       SENNE V. KANSAS CITY ROYALS BASEBALL

difference in this litigation.” Mazza, 666 F.3d at 590. For
example, some states have more expansive definitions of
“work,” others have differing available defenses, and we
have previously held that the elements for a quantum meruit
claim—alleged in both the Arizona and Florida classes—
“vary materially from state to state.” Id. at 591 (citing
Candace S. Kovacic, A Proposal to Simplify Quantum
Meruit Litigation, 35 Am. U.L. Rev. 547, 558–60 (1986)).

                                2.

    “Because the relevant laws differ,” we must “next
examine each jurisdiction’s interest in the application of its
own law under the circumstances of the particular case to
determine whether a true conflict exists.” Sullivan, 254 P.3d
at 245 (alteration, internal quotation marks, and citation
omitted). We are not persuaded, as defendants contend, that
a “true” conflict exists.

    First, under California’s choice-of-law principles, “a
jurisdiction ordinarily has the predominant interest in
regulating conduct that occurs within its borders.” 9 Mazza,
666 F.3d at 592 (internal quotation marks omitted) (quoting
McCann v. Foster Wheeler LLC, 225 P.3d 516, 534 (Cal.
2010)). The dissent contends that “California has long
rejected” this approach. Dissent at 71. In noting these
principles, we do not ignore the evolution of California’s
choice of law doctrine. We recognize that the California
Supreme Court “renounced the prior rule, adhered to by
courts for many years, that in tort actions the law of the place

     9
       Wage and hour laws are typically categorized as “conduct-
regulating,” as opposed to “loss-allocating.” See Professors’ Amicus
Brief at 15–16 (citing Hay, Borchers & Symeonides, Conflict of Laws
874–78 (5th ed. 2010)).
          SENNE V. KANSAS CITY ROYALS BASEBALL                         31

of the wrong was the applicable law in a California forum
regardless of the issues before the court” when it adopted the
governmental interest approach. Hurtado v. Superior Court,
522 P.2d 666 (Cal. 1974). Yet the California Supreme Court
has acknowledged that while it “no longer follows the old
choice-of-law rule that generally called for application of the
law of the jurisdiction in which a defendant’s allegedly
tortious conduct occurred without regard to the nature of the
issue that was before the court . . . California choice-of-law
cases nonetheless continue to recognize that a jurisdiction
ordinarily has the predominant interest in regulating conduct
that occurs within its borders.” McCann 225 P.3d at 534
(internal quotation marks and citation omitted) (emphasis in
original).

    Thus, when conducting the governmental interest
analysis, we must also recognize that a state ordinarily has
the predominant interest in regulating conduct within its
borders. We draw this conclusion not from California’s
interest in regulating conduct within its own borders, but
from California’s choice-of-law principles. 10 Thus these

    10
       See e.g., McCann, 225 P.3d at 534, 537 (recognizing that although
California no longer uniformly applied the law of the jurisdiction in
which the allegedly tortious conduct occurred, Oklahoma’s interests
“would be more impaired if its law were not applied” as the plaintiff’s
exposure to asbestos occurred in Oklahoma); Reich v. Purcell, 67 432
P.2d 727, 730 (Cal. 1967) (“Missouri is concerned with conduct within
her borders and as to such conduct she has the predominant interest of
the states involved.”); Castro v. Budget Rent-A-Car Sys., Inc., 65 Cal.
Rptr. 3d 430, 442 (Cal. Ct. App. 2007) (“The accident and Castro's injury
occurred within Alabama's borders, thus giving Alabama a presumptive
interest in controlling the conduct of those persons who use its roadways,
absent some other compelling interest to be served by applying
California law.”); Hernandez v. Burger, 162 Cal. Rptr. 564, 568 (Cal. Ct.
App. 1980) (“It is true that the place of the wrong is no longer treated as
a controlling factor where application of the law of another jurisdiction
32        SENNE V. KANSAS CITY ROYALS BASEBALL

principles are not limited to the California class but apply to
the Florida and Arizona classes as well. See Mazza, 666 F.3d
at 593 (“The district court did not adequately recognize that
each foreign state [not just California] has an interest in
applying its law to transactions within its borders.”). The
district court erred in ignoring these principles as a starting
point, instead faulting plaintiffs for not addressing “in detail
the interests of either Arizona or Florida in applying their
law” and focusing on the absence of Florida or Arizona cases
akin to Sullivan—despite the strong indications that Arizona
and Florida have the “predominant interest” in applying their
laws to work performed within their state. See Mazza, 666
F.3d at 592.

     Second, Sullivan relied on several different
considerations to arrive at its conclusion that the existence
of a true conflict was “doubtful, at best”: (1) the states in
which the employees resided did not express an intent to
apply their laws extraterritorially; (2) the employees’ states
of residence did not have a “legitimate interest” in shielding
an employer from California’s wage laws as to work
performed in California; and (3) federalism and due process
made extraterritorial reach doubtful under the
circumstances. See 254 P.3d at 245–47. Although
defendants vigorously argue that the first of those rationales
is inapplicable here—as discussed in greater detail below—
at a minimum, the second and third rationales do apply, and
weigh against the existence of a true conflict.


having a connection with the accident will serve a legitimate interest or
policy of the other jurisdiction. However, the situs of the injury remains
a relevant consideration.”); Cable v. Sahara Tahoe Corp., 155 Cal. Rptr.
770, 777 (Cal. Ct. App. 1979) (“The state with the ‘predominant’ interest
in controlling conduct normally is the state in which such conduct occurs
and is most likely to cause injury.”).
          SENNE V. KANSAS CITY ROYALS BASEBALL                      33

    As to the first rationale, both defendants and the dissent
contend that several states have expressed an interest in
applying their wage and hour laws to work performed
outside the state. In support of their position, they cite to a
handful of cases where courts (largely district courts or
intermediate state courts, with the exceptions of West
Virginia and Washington) 11 have applied one state’s wage
laws to work performed at least partially in another state.
For several reasons, we are unpersuaded by defendants’
arguments. For one, we read Sullivan as indicating that
under California’s choice-of-law principles, a state has a
legitimate interest in applying its wage laws extraterritorially
only in two limited circumstances, neither of which apply
here: one, when a state’s resident employee of that state’s
resident employer leaves the state “temporarily during the
course of the normal workday,” and two, “when the
traveling, resident employee of a domestic employer would
otherwise be left without the protection of another state’s


    11
        In New v. Tac & C Energy, Inc., 355 S.E.2d 629 (W. Va. 1987),
the West Virginia Supreme Court of Appeals applied its own conflict-
of-laws principles—relying on the Restatement (Second) of Conflicts
§ 196—to conclude that while there was a presumption that the law of
the state where services were rendered applies, the presumption could be
overcome by showing that another state had a “more significant
relationship to the transaction and the parties.” Id. at 631. Where all
parties were residents of West Virginia, the employment contract was
made and partially performed in West Virginia, and the plaintiffs were
only in Kentucky for the duration of the work, the court concluded that
the presumption was overcome and that West Virginia “had the more
significant connection to the employment relationship.” Id. California’s
choice-of-law test, of course, does not utilize the “more significant
relationship” test for choice-of-law questions in the wage and hour
context. See Sullivan, 254 P.3d at 244. New is therefore unpersuasive
here. We discuss the Washington Supreme Court case below.
34        SENNE V. KANSAS CITY ROYALS BASEBALL

law.” Id. at 242, 246 (citations, internal quotation marks,
and alterations omitted).

    Moreover, the cases on which defendants and the dissent
rely are, in large part, both factually and procedurally
inapposite to the circumstances of this case. 12 For example,
defendants rely heavily on Bostain v. Food Exp., Inc., 153
P.3d 846, 851 (Wash. 2007) to argue that Washington has an
interest in applying its wage laws extraterritorially. As the
California Supreme Court held in Sullivan, however, Bostain
“says nothing about a case such as this”—that is, a case
which (1) involves work performed entirely in one state, and
(2) presents an unavoidable conflict-of-laws issue. 254 P.3d
at 243. In Bostain, by contrast, either Washington law
applied to the work performed in both Washington and other
states, or else no state’s law applied. Id. at 243, 246.
Significantly, Bostain interpreted an overtime statute that
specifically delineated the circumstances under which its
provisions would apply to interstate truck drivers; as the
Washington Supreme Court noted, interstate truck drivers by
definition perform some of their work out of state. 153 P.3d
at 848–51. The statute at issue in Bostain did “not limit the
requirement for overtime pay to hours worked” within the
state’s borders. Id. at 851. Similarly, here, defendants point

     12
        Defendants’ repeated citation to Gonyou v. Tri-Wire Eng'g Sols.,
Inc., 717 F. Supp. 2d 152 (D. Mass. 2010) is illustrative. In Gonyou, a
Massachusetts resident employee of a Massachusetts employer worked
largely, although not entirely, in Connecticut. Id. at 153–54. The
defendant filed a motion to dismiss on the ground that the Massachusetts
overtime statute did not apply to work performed in Connecticut. Id. at
154–55. The court denied the motion but emphasized the limited nature
of its ruling: “As is eminently clear, this is a motion to dismiss and this
ruling is strictly limited to the facts and circumstances of this case and
this motion.” Id. at 155.
          SENNE V. KANSAS CITY ROYALS BASEBALL                         35

to no state statutes potentially applicable to the Arizona and
Florida class members that limit their application to work
performed within the state.

                                    3.

    Although the existence of a “true” conflict is
questionable, we need not decide whether a true conflict
exists, as the third step of California’s governmental interest
test yields a clear answer: the laws of Arizona and Florida
should apply to the work performed wholly within their
respective boundaries. 13 See Sullivan, 254 F.3d at 247. As
the California Supreme Court has explained the step three
inquiry:

         [T]he court does not “weigh” the conflicting
         governmental interests in the sense of
         determining    which     conflicting    law
         manifested the “better” or the “worthier”

     13
        Furthermore, in many of the cases cited by the dissent to
demonstrate that some states have asserted an interest in applying their
wage and hour laws outside of their borders, courts have looked closely
at where the relevant work is performed. See e.g., Pierre v. Gts
Holdings, Inc., No. 15 CIV. 143 (PAC), 2015 WL 7736552, at *3–*4
(S.D.N.Y. Nov. 30, 2015) (concluding that New York labor laws apply
because, among other things, the majority of the plaintiff’s chauffeured
rides were conducted in New York); Baxi v. Ennis Knupp & Assocs.,
Inc., No. 10-CV-6346, 2011 WL 3898034, at *14 (N.D. Ill. Sept. 2,
2011) (denying a motion to dismiss Illinois labor law claims because the
plaintiff, a foreign resident, performed some work in Illinois); Friedrich
v. U.S. Computer Sys., Inc., No. CIV. A. 90-1615, 1996 WL 32888, at
*8 (E.D. Pa. Jan. 22, 1996) (concluding that a Pennsylvania labor law
applies to the plaintiffs because the jury found the plaintiffs were “based
in Pennsylvania,” even if they were not residents of the state); Dow, 989
N.E.2d at 914 (concluding that Massachusetts law applied because,
given the nature of the plaintiff’s work, the work “sensibly may be
viewed as having ‘occurred’ in Massachusetts”).
36      SENNE V. KANSAS CITY ROYALS BASEBALL

       social policy on the specific issue. An
       attempted balancing of conflicting state
       policies in that sense is difficult to justify in
       the context of a federal system in which,
       within constitutional limits, states are
       empowered to mold their policies as they
       wish. Instead, the process can accurately be
       described as a problem of allocating domains
       of law-making power in multi-state
       contexts—by determining the appropriate
       limitations on the reach of state policies—as
       distinguished from evaluating the wisdom of
       those policies. Emphasis is placed on the
       appropriate scope of conflicting state policies
       rather than on the “quality” of those policies.

McCann, 225 P.3d at 533–34 (alterations and citations
omitted) (emphasis added).

    As discussed above, in Mazza, we faithfully applied the
principle under California’s choice-of-law jurisprudence
that “a jurisdiction ordinarily has the predominant interest in
regulating conduct that occurs within its borders.” Mazza,
666 F.3d at 592 (internal quotation marks omitted) (quoting
McCann, 225 P.3d at 534). We thus had no trouble
concluding at step three that “each class member’s consumer
protection claim should be governed by the consumer
protection laws of the jurisdiction in which the transaction
took place.” Id. at 594. Notably, we reached this conclusion
without specifically inquiring into the interests potentially
expressed by any state’s statutory language or case law.
Rather, our conclusion was dictated by the principle,
discussed above, that a jurisdiction ordinarily has the
predominant interest in regulating conduct within its own
borders. Id. at 591–92 (first citing State Farm Mut. Auto.
        SENNE V. KANSAS CITY ROYALS BASEBALL               37

Ins. Co. v. Campbell, 538 U.S. 408, 422 (2003); and then
citing McCann, 225 P.3d at 534).

    Moreover, in Sullivan, the court concluded that to
subordinate California’s ability to apply its own wage laws
to work performed within the state would “unquestionably”
cause greater impairment to California than to the states that
might seek to apply their wage laws to work performed by
their residents within California. 254 P.3d at 247. As
described previously, while this holding was influenced by
the absence of an expression of interest by Arizona or
Colorado in applying their laws extraterritorially, it did not
rise or fall on that ground. See id. at 244–47. And although
defendants point to a handful of cases that have entertained
the potential application of one state’s wage laws to work
performed in another state, they have not pointed to a single
state with a potentially-applicable statute that expresses a
clear interest in applying to work performed wholly outside
the state.

    But even if defendants were able to identify any states
that had unambiguously expressed an interest in applying
their wage laws to work performed entirely in another state,
Sullivan strongly militates against concluding that such an
expression of interest would be adequate to overcome the
principle that the state in which the conduct at issue occurs
has the “predominant interest” in applying their own law.
See Mazza, 666 F.3d at 592–94; Sullivan, 254 P.3d at 245–
47. Forcing Arizona or Florida to allow the application of
other states’ wage laws in this case would be just as
destructive to the balance Arizona and Florida have struck
between protecting workers and fostering a hospitable
business environment within their states as allowing the
application of Colorado or Arizona law in Sullivan would
have been to the balance California struck between those
38        SENNE V. KANSAS CITY ROYALS BASEBALL

same interests. See Sullivan, 254 P.3d at 246–47. The
district court fundamentally misunderstood the proper
application of California’s choice-of-law principles—which,
when correctly applied, indicate that Arizona law should
govern the Arizona class, and Florida law the Florida class.

                                C.

    We next address whether the district court erred in
refusing to certify a Rule 23(b)(2) class for unpaid work at
defendants’ training facilities in Arizona and Florida on the
sole basis that choice-of-law issues undermined
“cohesiveness” and therefore made injunctive and
declaratory relief inappropriate. Because the district court’s
errors in its choice-of-law analysis relating to the proposed
Arizona and Florida Rule 23(b)(3) classes apply equally to
its refusal to certify the proposed Rule 23(b)(2) class, we
also reverse the denial of the (b)(2) class.

    We further hold that the district court erred in imposing
a “cohesiveness” requirement for the proposed Rule 23(b)(2)
class. Although we have never explicitly addressed whether
“cohesiveness” is required under Rule 23(b)(2), courts that
have imposed such a test treat it similarly to Rule 23(b)(3)’s
predominance inquiry14—something we have previously
rejected in no uncertain terms. See Walters v. Reno, 145 F.3d
1032, 1047 (9th Cir. 1998) (“[W]ith respect to 23(b)(2) in
particular, the government’s dogged focus on the factual
differences among the class members appears to

     14
        The similarity between “cohesiveness” and predominance is
perhaps unsurprising, given that the Supreme Court described the
predominance inquiry under 23(b)(3) as testing whether a class is
“sufficiently cohesive to warrant adjudication by representation.”
Amchem Products, Inc. v. Windsor, 521 U.S. 591, 623 (1997) (emphasis
added).
          SENNE V. KANSAS CITY ROYALS BASEBALL                       39

demonstrate a fundamental misunderstanding of the rule.
Although common issues must predominate for class
certification under Rule 23(b)(3), no such requirement exists
under 23(b)(2).”); see also 2 Newberg on Class Actions
§ 4:34 (5th ed. 2012) (describing similarity between
predominance under Rule 23(b)(3) and “cohesiveness”
under Rule 23(b)(2) in courts that have adopted it). We
therefore remand for the district court to consider anew
whether to certify the proposed Rule 23(b)(2) class. 15

                                  III.

    Having addressed the impact of choice-of-law questions,
we turn to the issue next up at bat: whether the district court
erred in concluding that plaintiffs could meet the
predominance requirement for the proposed California,
Florida, and Arizona (b)(3) classes through a combination of
representative evidence and application of the “continuous
workday” rule.

    Rule 23(b)(3)’s predominance requirement requires
courts to ask “whether the common, aggregation-enabling
issues in the case are more prevalent or important than the
non-common, aggregation-defeating, individual issues.”
Tyson Foods, Inc. v. Bouaphakeo, 136 S. Ct. 1036, 1045
(2016) (quoting 2 Newberg on Class Actions § 4:49 (5th ed.
2012)). A proposed (b)(3) class may be certified as long as
“one or more of the central issues in the action are common
to the class and can be said to predominate . . . even though
other important matters will have to be tried separately, such
    15
        While the parties advanced numerous arguments regarding (b)(2)
certification in the district court, and advance similar arguments—along
with a few new ones—before us, we decline to pass on those other issues
in the first instance. See Stockwell, 749 F.3d at 1113, 1116–17; Davis v.
Nordstrom, Inc., 755 F.3d 1089, 1094–95 (9th Cir. 2014).
40      SENNE V. KANSAS CITY ROYALS BASEBALL

as damages or some affirmative defenses peculiar to some
individual class members.” Id. (quoting 7AA C. Wright, A.
Miller, & M. Kane, Federal Practice and Procedure § 1778
(3d ed. 2005)).

    “[P]redominance in employment cases is rarely defeated
on the grounds of differences among employees so long as
liability arises from a common practice or policy of an
employer.” 7 Newberg on Class Actions § 23:33 (5th ed.
2012). Although the existence of blanket corporate policies
is not a guarantee that predominance will be satisfied, such
policies “often bear heavily on questions of predominance
and superiority.” In re Wells Fargo Home Mortg. Overtime
Pay Litig., 571 F.3d 953, 958 (9th Cir. 2009).

     Whether the district court was correct in concluding that
plaintiffs had satisfied the predominance requirement hinges
on the application of two longstanding wage-and-hour
doctrines to this case: first, the burden-shifting framework
initially set forth in the Supreme Court’s seminal decision in
Anderson v. Mt. Clemens, 328 U.S. 680 (1946) and recently
expanded upon in Tyson Foods v. Bouaphakeo, 136 S. Ct.
1036 (2016); and second, the so-called “continuous
workday” rule. We address each of these doctrines and their
application to this case in turn.

                             A.

    In Mt. Clemens, the Supreme Court acknowledged the
difficult bind that employees frequently confronted when
seeking to bring wage-and-hour claims against their
employers: if their employers had failed to maintain proper
timekeeping records, proving the hours of uncompensated
work often posed “an impossible hurdle for the employee.”
328 U.S. at 687. Mt. Clemens held that such a catch-22 was
          SENNE V. KANSAS CITY ROYALS BASEBALL                       41

not in line with “the remedial nature of [the FLSA] 16 and the
great public policy which it embodies.” Id. After all, “[s]uch
a result would place a premium on an employer’s failure to
keep proper records in conformity with his statutory duty; it
would allow the employer to keep the benefits of an
employee’s labors without paying due compensation.” Id.

    To address this problem, Mt. Clemens established its
landmark burden-shifting framework for actions in which
the employer has kept inaccurate or inadequate records: if an
employee “proves that he has in fact performed work for
which he was improperly compensated” and “produces
sufficient evidence to show the amount and extent of that
work as a matter of just and reasonable inference,” then the
burden “shifts to the employer to come forward with
evidence of the precise amount of work performed or with
evidence to negative the reasonableness of the inference to
be drawn from the employee’s evidence.” Id. at 687–88. If
the employer does not rebut the employee’s evidence,
damages may then be awarded to the employee, “even
though the result be only approximate.” Id. at 688.

     Mt. Clemens explicitly rejected the notion that allowing
approximate damages in such situations would be unfair due
to its speculative and imprecise nature or because employers
sometimes make good-faith mistakes over what constitutes
compensable “work”:



    16
       Although Mt. Clemens was decided under the FLSA, its holding
has been consistently applied in the context of state wage-and-hour
claims as well. See, e.g., Tyson, 136 S. Ct. at 1045–48; Torres v. Mercer
Canyons Inc., 835 F.3d 1125, 1140 (9th Cir. 2016); Hernandez v.
Mendoza, 245 Cal. Rptr. 36, 39–40 (Cal. Ct. App. 1988) (applying Mt.
Clemens to claims under California wage and hour law).
42      SENNE V. KANSAS CITY ROYALS BASEBALL

       The employer cannot be heard to complain
       that the damages lack the exactness and
       precision of measurement that would be
       possible had he kept records in accordance
       with the [statutory] requirements . . . And
       even where the lack of accurate records
       grows out of a bona fide mistake as to
       whether certain activities or non-activities
       constitute work, the employer, having
       received the benefits of such work, cannot
       object to the payment for the work on the
       most accurate basis possible under the
       circumstances . . . In such a case it would be
       a perversion of fundamental principles of
       justice to deny all relief to the injured person,
       and thereby relieve the wrongdoer from
       making any amend for his acts.

Id. (internal quotation marks and citation omitted).

    Seventy years after Mt. Clemens addressed the use of
representative evidence at the trial stage to show damages,
Tyson extended Mt. Clemens’ holding to answer two
important questions: whether representative evidence may
be used at the class certification stage, and whether
representative evidence may also be used to establish
liability in addition to damages. In Tyson, employees who
worked in more than 400 jobs across three departments at a
meat processing plant sued under the FLSA and an Iowa
wage law, alleging that Tyson had not paid them overtime
for time they spent donning and doffing protective gear; the
employees also sought certification of a Rule 23 class and a
FLSA collective action. 136 S. Ct. at 1041–42.

    The district court certified the class and collective
actions, rejecting Tyson’s arguments that the claims were
         SENNE V. KANSAS CITY ROYALS BASEBALL                      43

inappropriate for resolution on a classwide and collective
basis due to the dissimilarity in the types of protective gear
worn and the variations in time spent donning and doffing
that gear. Id. at 1042–43. Because Tyson had not kept
records of the donning and doffing time, plaintiffs relied on
representative evidence to demonstrate both liability17 and
damages: employee testimony, video recordings, and—most
significantly—an expert study that computed an estimated
amount of time spent donning and doffing for each of the
three departments based on hundreds of video observations.
Id. at 1043. Although the expert estimated that the time
spent donning and doffing was 18 minutes per day for two
of the departments and 21.25 minutes for the other, id., the
survey data showed a great deal of variation in how long it
took individual employees to don and doff. Id. at 1055
(Thomas, J., dissenting). Specifically, the time spent
donning ranged from around thirty seconds to more than ten
minutes, and the time doffing varied from under two minutes
to over nine minutes. Id. After a jury verdict in the
employees’ favor (albeit one that awarded less than half of
the damages recommended by the employees’ expert based
on the survey data), Tyson moved to decertify the class and
set aside the jury verdict, arguing that this variance made
class and collective certification inappropriate. Id. at 1044–



     17
        Because the employees brought only overtime claims (as opposed
to minimum wage or other wage claims), “each employee had to show
he or she worked more than 40 hours a week, inclusive of time spent
donning and doffing, in order to recover.” Tyson, 136 S. Ct. at 1043.
That the majority permitted the use of representative evidence to
establish “an otherwise uncertain element of liability”—i.e., whether
class members worked more than 40 hours per week—was one of the
key bases for Justice Thomas’s vigorous dissent. See id. at 1057–59
(Thomas, J., dissenting).
44       SENNE V. KANSAS CITY ROYALS BASEBALL

45. The district court denied the motion, and the Eighth
Circuit affirmed. Id.

    Tyson sought certiorari on the grounds that using
representative evidence “manufactures predominance by
assuming away the very differences that make the case
inappropriate for classwide resolution,” “absolves each
employee of the responsibility to prove personal injury,” and
strips the employer of their ability to “litigate its defenses to
individual claims.” Id. at 1046. Rejecting these arguments,
the Supreme Court affirmed the class and collective
certifications. Id. at 1046–47. Because of Tyson’s
dereliction of their recordkeeping duties, the employees
were entitled to “introduce a representative sample to fill an
evidentiary gap created by the employer's failure to keep
adequate records.” Id. at 1047. The Court held that if the
representative sample introduced were admissible and
“could have sustained a reasonable jury finding as to hours
worked in each employee's individual action, that sample is
a permissible means of establishing the employees' hours
worked in a class action.” Id. at 1046–47.

    Stated another way, Tyson concluded that even where
“reasonable minds may differ” about whether representative
evidence is sufficiently probative of the requirements for
liability for a particular cause of action—in Tyson, whether
it was probative of the “time actually worked by each
employee”—that question is to be resolved by the jury, not
at the class certification stage. Id. at 1049 (“The District
Court could have denied class certification on this ground
[whether the representative evidence was “probative as to
the time actually worked by each employee”] only if it
concluded that no reasonable juror could have believed that
the employees spent roughly equal time donning and
doffing.”) (emphasis added). If the proffered representative
          SENNE V. KANSAS CITY ROYALS BASEBALL                       45

evidence, however, were “statistically inadequate or based
on implausible assumptions,” it “could not lead to a fair or
accurate estimate of the uncompensated hours an employee
has worked.” Id. at 1048–49. But where the evidence is
admissible—for expert evidence, using the Daubert
standard—then the “no reasonable juror” standard at the
class certification stage applies. See id. at 1049.

                                    B.

    Having established the parameters of when
representative evidence may be used at the class certification
stage, we address the second significant wage-and-hour
doctrine relevant to this case: the “continuous workday”
rule. The rule was first promulgated by the Department of
Labor (DOL) consistent with the Supreme Court’s decisions
interpreting the FLSA prior to the enactment of the Portal-
to-Portal Act 18 in 1947. IBP, Inc. v. Alvarez, 546 U.S. 21,
27–28 (2005). It presumes that once the beginning of the

    18
       In response to what Congress perceived as excessively expansive
judicial interpretations of what constitutes compensable work under the
FLSA, IBP, 546 U.S. at 27–28, it passed the Portal-to-Portal Act to
exempt certain activities as compensable under FLSA:

         “(1) walking, riding, or traveling to and from the actual
         place of performance of the principal activity or
         activities which such employee is employed to
         perform, and

         (2) activities which are preliminary to or postliminary
         to said principal activity or activities,

which occur either prior to the time on any particular workday at which
such employee commences, or subsequent to the time on any particular
workday at which he ceases, such principal activity or activities.” 61
Stat. 86–87 (codified at 29 U.S.C. § 254(a)).
46      SENNE V. KANSAS CITY ROYALS BASEBALL

workday is triggered, an employee performs compensable
work throughout the rest of the day until the employee
completes their last principal activity (or the last activity
which is “integral and indispensable” to the employee’s
principal activities)—whether or not the employee actually
engages in work throughout that entire period. See id. at 28,
32–37; see also Alvarez v. IBP, Inc., 339 F.3d 894, 907 (9th
Cir. 2003), aff’d, 546 U.S. 21 (2005) (holding that under the
continuous workday rule, “work time [is] continuous, not the
sum of discrete periods”).

    Of course, this rule raises inevitable questions: when
does the workday begin, and when does it end? The DOL
defines the “workday” to generally mean “the period
between the commencement and completion on the same
workday of an employee's principal activity or activities.”
29 C.F.R. § 790.6(b). The Supreme Court expanded upon
this definition, interpreting “principal activity or activities”
to also include “all activities which are an integral and
indispensable part of the principal activities.” IBP, 546 U.S.
at 29–30 (internal quotation marks and citation omitted).
Thus, any activity which is “integral and indispensable” to
principal activities, even if performed outside of a scheduled
shift, triggers the beginning of the “workday.” Id. at 31–37.
“Among the activities included as an integral part of a
principal activity are those closely related activities which
are indispensable to its performance,” 29 C.F.R. § 790.8(c),
such as knife-sharpening performed outside of a scheduled
shift by butchers at a meatpacking plant. Mitchell v. King
Packing Co., 350 U.S. 260, 261–63 (1956).

                              C.

   With all of that in mind, we turn to how these two
doctrines impact this case, and more specifically, whether
the district court was correct in concluding that the
         SENNE V. KANSAS CITY ROYALS BASEBALL                     47

combination of Tyson and the continuous workday rule
enabled plaintiffs to show that they meet Rule 23(b)(3)’s
predominance requirement. Defendants contend that the
district court erred in holding that plaintiffs had
demonstrated predominance for two main reasons:
(1) because the Main Survey asked only about arrival and
departure times at the ballpark and not about what activities
the players actually performed while at the ballpark,
plaintiffs cannot rely on the continuous workday theory
because there is no way to determine the beginning or end of
the “workday,” and (2) the Main Survey revealed significant
variations in players’ arrival and departure times, even
among players employed by the same MLB franchise.

    This task requires us to address the proposed Arizona
and Florida classes separately from the California class. As
an initial matter, however, we note that despite defendants’
repeated suggestions to the contrary, the representative
evidence offered by plaintiffs was not limited to just the
Main Survey, nor are observational studies the only type of
evidence permitted to fill in evidentiary gaps under Tyson.
We reject defendants’ erroneous view of the record and their
cramped reading of Tyson.

                                 1.

    As to the Arizona and Florida classes, we easily affirm
the district court’s determination. Recall that these two
classes cover time spent participating in spring training,
extended spring training, and the instructional leagues—
periods during which virtually all players are completely
unpaid for their participation. 19 Moreover, these classes do

    19
       Payroll data produced by defendants reveals that of the 21,211
players who participated in spring training between the 2009 and 2015
48        SENNE V. KANSAS CITY ROYALS BASEBALL

not bring overtime claims, but rather allege minimum wage
violations. 20 Therefore—as the district court correctly
held—liability can be established simply by showing that the
class members performed any compensable work. 21 That is
easily resolved on a classwide basis by answering two
questions: (1) are the players employees of defendants, and
(2) do the minor league team activities during these periods
constitute compensable work under the laws of either
Arizona or Florida? We hold that these two “common,
aggregation-enabling issues in the case are more prevalent
[and] important than the non-common, aggregation-
defeating, individual issues,” therefore making certification
appropriate. Tyson, 136 S. Ct. at 1045 (quoting 2 Newberg
on Class Actions § 4:49 (5th ed. 2012)).

    Defendants do not seriously contest that their policy is to
deny players compensation during spring training, extended
spring training, and the instructional leagues—nor could
they credibly do so, given that the MLB’s own mandatory

seasons, only 11 were paid a salary. Put differently, a mere .005% of
players received a salary during spring training, and those 11 players
may be identified through payroll records and appropriately excluded
from the class. Likewise, a small number of MLB franchises pay players
during extended spring training, but these players are identifiable
through payroll records and may either be excluded from the class or,
potentially, placed into a subclass.
     20
        The Arizona and Florida classes also bring quantum meruit
claims, and the Arizona class alleges recordkeeping violations, but the
parties do not dispute that these claims are irrelevant to this portion of
our predominance analysis.

     21
       We also note that the Arizona class’s claims are bolstered by the
fact that under Arizona law, failure to keep appropriate records of hours
worked “raise[s] a rebuttable presumption that the employer did not pay
the required minimum wage rate.” Ariz. Rev. Stat. Ann. § 23-364.
        SENNE V. KANSAS CITY ROYALS BASEBALL               49

contract “obligates Player[s] to perform professional
services on a calendar year basis, regardless of the fact that
salary payments are to be made only during the actual
championship playing season.” And as we have long held,
such uniform corporate policies “carry great weight for
certification purposes.” In re Wells Fargo Home Mortg.
Overtime Pay Litig., 571 F.3d at 958. This is not the “rare[]”
case where predominance is defeated despite the existence
of an employer’s “common practice or policy.” 7 Newberg
on Class Actions § 23:33 (5th ed. 2012).

    We also agree with the district court that as to these
classes, many of defendants’ protests go to damages, not
liability. Damages may well vary, and may require
individualized calculations. But “the rule is clear: the need
for individual damages calculations does not, alone, defeat
class certification.” Vaquero v. Ashley Furniture Indus.,
Inc., 824 F.3d 1150, 1155 (9th Cir. 2016); see Tyson, 136
S. Ct. at 1045 (holding that where “one or more of the central
issues in the action are common to the class and can be said
to predominate,” certification may be appropriate “even
though other important matters will have to be tried
separately, such as damages.” (quoting 7AA C. Wright, A.
Miller, & M. Kane, Federal Practice and Procedure § 1778
(3d ed. 2005))).

     We do not, however, mean to minimize defendants’
criticisms of the Main Survey. Indeed, we agree that there
are a number of legitimate questions about the
persuasiveness of the Main Survey, especially if it were the
only representative evidence submitted in support of
certification. But as we have mentioned, the Main Survey
was but one piece of the plaintiffs’ representative
evidence—evidence that also included hundreds of internal
50        SENNE V. KANSAS CITY ROYALS BASEBALL

team schedules and public game schedules, payroll data, and
the testimony of both players and league officials.

     At minimum, if the players are “employees” under either
Arizona or Florida law and defendants are unable to prove
that any affirmative defenses apply, the team schedules will
serve to conclusively demonstrate that the players spent time
working for which they were uncompensated. See Ariz.
Rev. Stat. Ann. § 23-362; Ariz. Admin. Code. § R20-5-
1202(19) (“‘Hours worked’ means all hours for which an
employee covered under the Act is employed and required
to give to the employer, including all time during which an
employee is on duty or at a prescribed work place and all
time the employee is suffered or permitted to work.”);
29 C.F.R. § 778.223 (“As a general rule the term ‘hours
worked’ will include: (a) All time during which an employee
is required to be on duty or to be on the employer's premises
or at a prescribed workplace and (b) all time during which
an employee is suffered or permitted to work whether or not
he is required to do so.”). 22 Moreover, if plaintiffs can
persuade a jury that their workday began at a particular
time—either because they were required to report at that
time, 23 or because they arrived of their own volition but

     22
       We rely on interpretations of the FLSA here because Florida’s
constitution provides that “case law, administrative interpretations, and
other guiding standards developed under the federal FLSA shall guide
the construction of [the constitutional amendment providing for a
minimum wage] and any implementing statutes or regulations.” Fla.
Const. art. X, § 24.

    23
       See 29 C.F.R. § 790.6 (“If an employee is required to report at the
actual place of performance of his principal activity at a certain specific
time, his ‘workday’ commences at the time he reports there for work in
accordance with the employer's requirement.”).
          SENNE V. KANSAS CITY ROYALS BASEBALL                        51

engaged in work activities upon arriving (i.e., were
“permitted” to work)—the continuous workday doctrine
eliminates the need for plaintiffs to prove which activities
they engaged in throughout the day. 24 See IBP, 546 U.S. at
28, 32–37.

    Defendants should not “be heard to complain that the
damages lack the exactness and precision of measurement
that would be possible had [they] kept records in accordance
with the [statutory] requirements,” even if their “lack of
accurate records grows out of a bona fide mistake as to
whether certain activities or non-activities constitute work.”
Mt. Clemens, 328 U.S. at 688. “Having received the benefits
of such work, [defendants] cannot object to the payment for
the work on the most accurate basis possible under the
circumstances.” Id.

                                   2.

    We next address whether the district court was correct to
hold that predominance had been met for the California
class. Given the differences in the types of claims brought
by the California class as compared to the Arizona and
Florida classes, certification of the California class is more
complex and requires additional analysis. Unlike the
Arizona and Florida classes, the California class brought
claims relating to work performed during the championship
season—a time when the players do get paid, albeit not
much. As a result, in order to prove liability on their
overtime claims, the California class must show that its
    24
        A jury may also decide that for baseball players, activities like
hitting practice with coaches and supervised weightlifting—much like
knife-sharpening by butchers at a meatpacking plant— are “integral and
indispensable” to the principal activity of playing baseball and therefore
trigger the start of the “workday.” See Mitchell, 350 U.S. at 261–63.
52      SENNE V. KANSAS CITY ROYALS BASEBALL

members worked more than 8 hours in a day, more than 40
hours in a week, and/or worked 7 days in a workweek. See
Cal. Labor Code § 510; Mendoza v. Nordstrom, Inc., 393
P.3d 375, 381–82 (Cal. 2017). Likewise, to establish
liability on their minimum wage claims, the California class
must demonstrate that they worked hours for which they
were not paid at least minimum wage—but whereas the
Arizona and Florida classes can demonstrate liability simply
by showing they worked any hours, the California class’s
burden is made more challenging by the fact that the players
receive some pay. See Cal. Labor Code §§ 1182 et seq;
Armenta v. Osmose, Inc., 37 Cal. Rptr. 3d 460, 466–68 (Cal.
Ct. App. 2005). Nonetheless, a number of considerations
lead us to affirm the district court’s determination.

    First, as with defendants’ uniform policy of not paying
players for participation outside of the championship season,
defendants do not credibly dispute that their policy is to
never pay overtime and to pay a fixed salary, regardless of
the actual number of hours worked. We reiterate that
common corporate policies like this “carry great weight for
certification purposes,” In re Wells Fargo Home Mortg.
Overtime Pay Litig., 571 F.3d at 958, and that predominance
is “rarely” defeated in cases where such uniform policies
exist. See 7 Newberg on Class Actions § 23:33 (5th ed.
2012).

   Second, the team schedules alone—independent of the
Main Survey or any other evidence—may suffice to show
overtime liability. As the district court noted, plaintiffs’
expert testified that approximately 65–85% of California
League players had at least one workweek with games on all
seven days, and that nearly half of all workweeks included
games on all seven days. For those workweeks, the players
        SENNE V. KANSAS CITY ROYALS BASEBALL               53

would be entitled to overtime pay for their work on the
seventh day of the workweek. See Cal. Labor Code § 510.

    Third, and most significantly, we are persuaded that
under Tyson, the representative evidence plaintiffs offered
was adequate to meet their burden at this stage. As we
observed in the preceding section, defendants do identify
multiple legitimate criticisms of the Main Survey, and it is
certainly possible that a jury may not find the Main Survey—
even in combination with all of plaintiffs’ other evidence—
adequate proof of liability (or at least not to the extent
plaintiffs allege). In particular, a jury may be persuaded by
defendants’ arguments that players did not begin
compensable work upon arriving at the ballpark or that
players stopped engaging in compensable work long before
they left the ballpark, such that the Main Survey’s estimated
arrival and departure times are insufficient to clear the
preponderance hurdle. As we explain below, however,
Tyson counsels that such criticisms do not doom certification
here unless no reasonable jury could conclude that the
combination of the Main Survey and plaintiffs’ other
representative evidence was probative of the amount of time
players actually spent performing compensable work. See
Tyson, 136 S. Ct. at 1046–49. And while defendants
correctly point out that the Main Survey revealed meaningful
variations in players’ arrival and departure times, the same
was true of the employees’ donning and doffing times in
Tyson—yet such variation did not preclude certification
there. See id. at 1043; id. at 1055 (Thomas, J., dissenting).

    Because defendants do not challenge the district court’s
ruling on admissibility under Daubert, the defects they have
identified with the Main Survey could only have defeated
certification upon a conclusion that all of the representative
evidence offered—the Main Survey, schedules, testimony,
54        SENNE V. KANSAS CITY ROYALS BASEBALL

and the like—could not have “sustained a reasonable jury
finding as to hours worked in each employee’s individual
action.” See Tyson, 136 S. Ct. at 1046–47. As in Tyson, the
district court “made no such finding,” id. at 1049, and indeed
found the opposite:

          Plaintiffs will be able to use the survey data
          in combination with other evidence that may
          be sufficient to allow a jury to draw
          conclusions based on reasonable inference as
          to when players were required to be at the
          ballpark and how long after games they were
          required to remain at the ballpark. . . . Thus,
          as in Tyson Foods, it appears that
          representative evidence can be combined
          with actual records of time spent engaged in
          the various activities to derive a reasonable
          estimate of the amount of time worked by
          class members.

We are then left to ask whether “the record here provides [a]
basis for [us] to second-guess that conclusion.” Id.

   After reviewing the record, we are satisfied that we
should not disturb the district court’s determination, in part
due to California’s expansive definition of “employ” and
“hours worked.” 25 Under California law, to “employ”

     25
       Unlike Arizona and Florida law—the former of which is silent on
the incorporation of FLSA doctrines, and the latter of which expressly
incorporates them—we are not persuaded that the continuous workday
rule should apply to the California class. We view California’s definition
of “hours worked” as more expansive and more employee-friendly than
under the FLSA, even with the incorporation of the continuous workday
rule. The California Supreme Court has “cautioned against confounding
federal and state labor law,” and has consistently held that “absent
          SENNE V. KANSAS CITY ROYALS BASEBALL                        55

means “to engage, suffer, or permit to work.” Cal. Code
Regs. tit. 8, §§ 11040(2)(E), 11100(2)(E) (emphasis
added). 26 “Hours worked” means “the time during which an
employee is subject to the control of an employer, and
includes all the time the employee is suffered or permitted to
work, whether or not required to do so.” Cal. Code Regs. tit.
8, §§ 11040(2)(K), 11100(2)(H). Inexplicably, however,
defendants claim that under California law, “time spent
engaging in activities that are not required by, or under the
control of, an employer is not compensable and does not
begin or extend a workday.” This is a tortured and wholly
unsupported reading of the law, and is manifestly contrary
to one of the cases defendants themselves cite in support of
their argument. See Morillion v. Royal Packing Co., 995
P.2d 139, 143 (Cal. 2000) (“[T]he two phrases—‘time
during which an employee is subject to the control of an
employer’ and ‘time the employee is suffered or permitted
to work, whether or not required to do so’—can also be
interpreted as independent factors, each of which defines
whether certain time spent is compensable as ‘hours
worked.’”) (citation omitted).




convincing evidence of the [California agency’s] intent to adopt the
federal standard for determining whether time is compensable under
state law, we decline to import any federal standard, which expressly
eliminates substantial protections to employees, by implication.”
Troester v. Starbucks Corp., 421 P.3d 1114, 1119 (Cal. 2018)
(alterations, citations, and internal quotation marks omitted).

    26
       The California Industrial Welfare Commission’s wage orders
“have the force of law.” Alvarado v. Dart Container Corp. of Cal., 411
P.3d 528, 532 (Cal. 2018). We need not decide today which wage order
applies to minor league players, as all of the most relevant orders define
“employ” and “hours worked” the same way.
56      SENNE V. KANSAS CITY ROYALS BASEBALL

     Indeed, Morillion counsels that “hours worked” includes
all time the employer “permit[s]” an employee to work, even
if the work is not required and the employee is not under the
employer’s control. See id. Thus, a player who arrives early
or stays late at the ballpark of their own volition and
performs “work” activities during that time is still owed
compensation because the player was “permitted” to work,
despite the work not being required.

    Likewise, under Morillion, if players were expected to
arrive or depart at a particular time—whether that
requirement was de facto or official—it is immaterial what
activities the players actually engaged in while at the
ballpark. Even if the players spent their time at the ballpark
doing things like eating or showering, they were still under
their employer’s control and unable “to use the time
effectively for their own purposes,” and thus were owed
compensation. See id. at 146. Indeed, Morillion explicitly
rejected an analogous argument by the employer in that case:

       We reject Royal’s contention that plaintiffs
       were not under its control during the required
       bus ride because they could read on the bus,
       or perform other personal activities.
       Permitting plaintiffs to engage in limited
       activities such as reading or sleeping on the
       bus does not allow them to use the time
       effectively for their own purposes . . .
       Plaintiffs were foreclosed from numerous
       activities in which they might otherwise
       engage if they were permitted to travel to the
       fields by their own transportation. Allowing
       plaintiffs the circumscribed activities of
       reading or sleeping does not affect, much less
       eliminate, the control Royal exercises by
        SENNE V. KANSAS CITY ROYALS BASEBALL                57

       requiring them to travel on its buses and by
       prohibiting them from effectively using their
       travel time for their own purposes. Similarly
       . . . listening to music and drinking coffee
       while working in an office setting can also be
       characterized as personal activities, which
       would not otherwise render the time working
       noncompensable.

Id. (alterations, internal quotation marks, and citations
omitted). Thus, if plaintiffs use their representative
evidence—especially the Main Survey and the testimony of
players and league officials—to persuade a jury that they
were required to be at the ballpark at particular times, they
need not show how the players spent that time.

    The fourth and final consideration weighing in favor of
affirming the district court’s determination is our standard of
review. Abuse of discretion is always a relatively deferential
standard, but when we review a grant of class certification,
“we accord the district court noticeably more deference than
when we review a denial.” Abdullah, 731 F.3d at 956
(citation omitted). Were we to review de novo, this would
likely be a closer call. But as they say, tie goes to the
runner—and, under our deferential standard, to the district
court.

                              D.

    Finally, defendants, citing to Wal-Mart Stores, Inc. v.
Dukes, 564 U.S. 338, 352 (2011), contend that the district
court was required to “rigorously analyze” the Main Survey,
rather than evaluating its admissibility under Daubert and its
appropriateness for meeting class certification requirements
under Tyson. Tyson requires that we reject this argument.
There, the Court explicitly distinguished the use of
58        SENNE V. KANSAS CITY ROYALS BASEBALL

representative evidence to establish hours worked in wage
and hour claims from the use of representative evidence in
cases like Wal-Mart.         Tyson, 136 S. Ct. at 1048.
Specifically—as we have explained—for wage and hour
cases where the employer has failed to keep proper records,
Tyson holds that once a district court has found expert
evidence to be admissible, it may only deny its use to meet
the requirements of Rule 23 certification if “no reasonable
juror” could find it probative of whether an element of
liability was met. Id. at 1049. Given the similarities between
this case and Tyson, the rule set forward in Tyson controls,
and “[defendants’] reliance on Wal-Mart is misplaced.” 27
Id. (citation omitted).

                                 IV.

    We next address whether the district court properly
certified the FLSA collective action.

    FLSA permits employees to bring lawsuits on behalf of
“themselves and other employees similarly situated.” 29
U.S.C. § 216(b). We recently delineated the appropriate
standard for FLSA collective certification in Campbell v.
City of Los Angeles, 903 F.3d 1090 (9th Cir. 2018). As we
explained in Campbell, “there is no established definition of
the FLSA’s ‘similarly situated’ requirement, nor is there an
established test for enforcing it.” Id. at 1111 (citing Thiessen
v. Gen. Elec. Capital Corp., 267 F.3d 1095, 1102 (10th Cir.
2001)). In Campbell, we rejected both the minority
approach to FLSA collective certification—which treats a
FLSA collective as analogous to a Rule 23(b)(3) class—and

     27
        Tyson expressly cautioned that this rule should be read narrowly
and not assumed to apply outside of the wage and hour context. 136
S. Ct. at 1049.
        SENNE V. KANSAS CITY ROYALS BASEBALL                59

the majority “ad hoc” approach. Id. at 1111–1117. The
former approach, we observed, is inconsistent with the
statute itself, as well as the choice of Congress and the
Advisory Committee on Rules to distinguish FLSA
collectives from Rule 23 class actions. Id. at 1111–1113.
And while the latter approach—the so-called ad hoc
approach—is a “significant improvement” over the minority
approach, it has two major flaws that led us to decline to
adopt it.      Id. at 1113–1116.        First, this approach
inappropriately “focus[es] on differences rather than
similarities among the party plaintiffs,” leading district
courts to “treat[] difference as disqualifying,” rather than
“treat[ing] the requisite kind of similarity as the basis for
allowing partially distinct cases to proceed together.” Id. at
1117. Second, because the ad hoc approach allows district
courts to weigh “fairness and procedural considerations,” it
“invites courts to import, through a back door, requirements
with no application to the FLSA,” such as Rule 23’s
predominance, adequacy, and superiority requirements. Id.
at 1115.

    Because of the flaws in the two predominant approaches
to FLSA collective certification, we instead developed our
own standard: “[p]arty plaintiffs are similarly situated, and
may proceed in a collective, to the extent they share a similar
issue of law or fact material to the disposition of their FLSA
claims.” Id. at 1117. Significantly, as long as the proposed
collective’s “factual or legal similarities are material to the
resolution of their case, dissimilarities in other respects
should not defeat collective treatment.” Id. at 1114
(emphasis omitted).

   The district court here did not have the benefit of our
opinion in Campbell, and instead followed the vast majority
of district courts in this circuit by applying the ad hoc
60        SENNE V. KANSAS CITY ROYALS BASEBALL

approach. See, e.g., Lewis v. Wells Fargo & Co., 669
F. Supp. 2d 1124, 1127 (N.D. Cal. 2009) (“Although various
approaches have been taken to determine whether plaintiffs
are ‘similarly situated,’ district courts in this circuit have
used the ad hoc, two-tiered approach.”). While legally
incorrect, we conclude that the district court’s erroneous use
of the ad hoc approach was harmless under the
circumstances, 28 and we affirm the collective’s certification.

    The district court found that plaintiffs met their burden
of demonstrating they were “similarly situated,” reasoning:

          First, by eliminating the winter conditioning
          claims and pursuing on a classwide basis only
          claims that are based on the continuous
          workday       doctrine,     Plaintiffs     have
          significantly reduced the need to engage in
          individualized inquiries relating to the type of
          work performed. Second, the Court is now
          persuaded that the payroll records maintained
          by Defendants will allow any variations in
          compensation to be analyzed without
          burdensome individualized inquiries. This is
          especially true as to the spring training,
          extended spring training and instructional
          league claims because players generally were
          not compensated for their participation in
          these activities and the small fraction of
          players who did receive compensation for
     28
       As we explained in Campbell, the ad hoc approach imposes a
higher bar for certification than the FLSA requires. See Campbell, 903
F.3d at 1114–1116. Thus, if the collective was appropriately certified
under the more stringent ad hoc approach, a fortiori the collective would
be appropriately certified under Campbell’s more lenient approach to
“similarly situated.” See id.
         SENNE V. KANSAS CITY ROYALS BASEBALL                 61

        these activities can be identified using payroll
        records maintained by Defendants. Third, as
        discussed above, the Court finds that the
        defenses asserted by Defendants to the FLSA
        present common questions that are not likely
        to be overwhelmed by the need to conduct
        individualized inquiries.         Finally, the
        possibility that the Court will be required to
        apply the laws of numerous states (or at a
        minimum, conduct numerous choice of law
        inquiries) is not present as to the FLSA class,
        which will require the Court to apply only
        federal wage and hour law.

    Defendants’ arguments in support of reversal echo those
they make in relation to the Rule 23(b)(3) classes, and we
reject them for largely the same reasons. Cf. Tyson, 136
S. Ct. at 1036 (“For purposes of this case . . . if certification
of respondents’ class action under [Rule 23] was proper,
certification of the collective action was proper as well.”).
We therefore expand on our earlier reasoning only briefly.

    Because the FLSA collective covers work performed
during spring training, extended spring training, and the
instructional leagues—that is, work for which the players
received no pay—we affirm the certification of the collective
for that work. Specifically, for these time periods, two
common legal questions drive the litigation: are the players
employees, and do the activities they perform during those
times constitute compensable work? As nearly all players
are unpaid during these time periods, if the answers to those
two questions are resolved in plaintiffs’ favor, liability may
be established by showing that the players performed any
work.
62      SENNE V. KANSAS CITY ROYALS BASEBALL

    We also affirm the district court’s certification of the
FLSA collective as to plaintiffs’ overtime claims, although
this holding requires additional explanation. Critical to our
decision is that plaintiffs allege a single, FLSA-violating
policy—the failure to pay overtime under any
circumstances—and argue a common theory of defendants’
statutory violations: that defendants “suffer or permit”
plaintiffs to perform compensable work before and after
scheduled practice and game times. These are “similar
issue[s] of law or fact material to the disposition of their
FLSA claims,” thus making plaintiffs “similarly situated.”
Campbell, 903 F.3d at 1117. And as previously discussed,
we believe a reasonable jury could find that all of plaintiffs’
evidence—not just the Main Survey, but also the schedules,
testimony, and payroll data—sustains a “just and reasonable
inference” as to the hours players actually worked. See
Tyson, 136 S. Ct. at 1046–47.

    Specifically, there are several overlapping ways that
plaintiffs may be able to rely on their representative evidence
to persuade a jury that they have worked overtime hours for
which they were not compensated. Under any of these
scenarios, the continuous workday rule lends significant
assistance to plaintiffs by eliminating the need for plaintiffs
to prove exactly which activities they engaged in throughout
the day. See IBP, 546 U.S. at 28, 32–37.

     First, plaintiffs could potentially use their evidence—
particularly the Main Survey, but also the testimony of
players and league officials—to establish approximate times
that they were required to arrive at and depart from the
ballpark. This would obviate the need for plaintiffs to
demonstrate which activities they engaged in upon arrival or
prior to departure. See 29 C.F.R. § 790.6 (“If an employee
is required to report at the actual place of performance of his
        SENNE V. KANSAS CITY ROYALS BASEBALL                 63

principal activity at a certain specific time, his ‘workday’
commences at the time he reports there for work in
accordance with the employer's requirement.”); 29 C.F.R.
§ 778.223 (“As a general rule the term ‘hours worked’ will
include . . . [a]ll time during which an employee is required
to be on duty or to be on the employer’s premises or at a
prescribed workplace.”) (emphasis added).

    Second, plaintiffs could rely on their representative
evidence to demonstrate that before and after the times they
were required to be at the ballpark, they still performed
activities at the ballpark that were “an integral and
indispensable part of [their] principal activities” and were
therefore compensable. See IBP, 546 U.S. at 29–30. As
mentioned previously, a jury may well determine that
activities like batting practice or supervised weightlifting are
to baseball players what knife-sharpening is to butchers at a
meatpacking plant—that is, activities that are “integral and
indispensable” to the principal activity of playing baseball.
See Mitchell, 350 U.S. at 261–63. If so, such activities
would trigger the start of the “workday” within the meaning
of the FLSA. Plaintiffs may have somewhat of an uphill
battle proceeding under this second theory on a collective-
wide basis, but we are certainly not prepared to say that no
reasonable jury could find defendants liable for overtime
violations under this theory. See Tyson, 136 S. Ct. at 1048–
49; cf. Campbell, 903 F.3d at 1117–1119 (explaining that
post-discovery decertification motions should be evaluated
under the summary judgment standard where “overlap exists
between the availability of the collective action mechanism
and the merits of the underlying claim”).

    Finally, if internal team schedules establish that
plaintiffs had required team-related activities for forty hours
64        SENNE V. KANSAS CITY ROYALS BASEBALL

a week, 29 then plaintiffs can establish liability simply by
showing that they performed any additional work beyond
those officially-scheduled times. Cf. Tyson, 136 S. Ct. at
1036 (Thomas, J., dissenting) (explaining that in Mt.
Clemens, the employer was “presumptively liable to all
employees because they all claimed to work 40 hours per
week. All additional uncompensated work was necessarily
unpaid overtime.”) (citation omitted).

    Under any of these theories, damages will inevitably be
individualized, at least to some extent. But just as the need
for individualized damage calculations is insufficient to
defeat Rule 23 certification, “[i]ndividual damages amounts
cannot defeat collective treatment under the more forgiving
standard” for FLSA collective certification. See Campbell,
903 F.3d at 1117 (citing Leyva v. Medline Indus. Inc., 716
F.3d 510, 514 (9th Cir. 2013)). District courts are well-
equipped to deal with issues of individualized calculations
in the wage-and-hour context, and may use “any of the
practices developed to deal with Rule 23 classes facing
similar issues.” Id. at 18 (citing Jimenez v. Allstate Ins. Co.,
765 F.3d 1161, 1167 (9th Cir. 2014)).



     29
        Given the internal team schedules in the record, this may be an
easy task, particularly for spring training and extended spring training.
For example, a spring training schedule for one of the San Francisco
Giants’ affiliates involved a workday beginning at 6:30 AM on the day
of a 1:00 PM away game, with a 50 minute window provided for transit
between the training facility and the ballpark. Assuming for the sake of
argument that the 1:00 PM game lasted 2.5 hours and that the return trip
to the training facility took the same amount of time—50 minutes—as
the outgoing trip, that day alone entailed approximately 10 hours of work
if the players left the training facility immediately upon their return (and
based on the testimony in the record, that assumption seems
implausible).
         SENNE V. KANSAS CITY ROYALS BASEBALL                 65

     As is true in all FLSA cases, underlying our decision
today is the background principle that “because the FLSA is
a remedial statute, it must be interpreted broadly.” Lambert
v. Ackerley, 180 F.3d 997, 1003 (9th Cir. 1999) (en banc)
(citing Tennessee Coal, Iron & R. Co. v. Muscoda Local No.
123, 321 U.S. 590, 597 (1944)). After all, the FLSA does
not deal “with mere chattels or articles of trade but with the
rights of those who toil.” Tennessee Coal, 321 U.S. at 597.
We are satisfied that certification of the collective is not only
appropriate under our interpretation of “similarly situated,”
but also that it is consistent with “the great public policy”
embodied by the FLSA. Mt. Clemens, 328 U.S. at 687.

                               V.

   For the reasons explained above, we AFFIRM in part,
REVERSE in part, and REMAND for further proceedings
consistent with this opinion.

    Plaintiffs-Appellants/Cross-Appellees       shall   recover
their costs on appeal.



IKUTA, Circuit Judge, dissenting:

    The proposed classes here comprise employees who
reside in at least 19 states, who are suing employers who are
headquartered in at least 22 states, relating to work that took
place in three different states. Determining whether to
certify a class in these cases would (among other things)
require identifying the relevant laws of each of the
potentially affected jurisdictions, examining each
jurisdiction’s interest in the application of its own law to
determine whether a true conflict exists, and then deciding
which jurisdiction’s interest would be most impaired if its
66      SENNE V. KANSAS CITY ROYALS BASEBALL

law were not applied. Sullivan v. Oracle Corp., 51 Cal. 4th
1191, 1202–03 (2011). No wonder the district court
concluded that consideration of the plaintiffs’ claims on a
classwide basis would be overwhelmed by individualized
choice-of-law inquiries.

    Yet the majority feels empowered to cut through all these
complexities by applying a simple rule of its devise: just
apply the law of the jurisdiction where the work took place.
Under this simple formula, each class can readily be certified
without any fuss. One may admire the simplicity of this
rule—but unfortunately, it is contrary to our framework for
analyzing the intersection of class action and choice-of-law
issues, overlooks the complexity of California’s choice-of-
law rules, and creates significant practical and logistical
problems. I therefore dissent.

                              I

    The plaintiffs in this case are current or former Minor
League Baseball players who played during the period from
2009 to 2015. They sued Major League Baseball (MLB)
(which they argue is a joint employer of all minor league
players) and the MLB Clubs for which they worked for
violations of federal and state labor laws, including the
federal Fair Labor Standards Act, state minimum wage laws,
and state overtime laws. The plaintiffs argue that they were
entitled to the minimum wage and overtime rates established
by California, Arizona, or Florida for work they performed
in those states.

    MLB is an unincorporated association headquartered in
New York. The MLB Clubs, which are corporate entities
that own MLB teams, are members of the MLB. All told,
there are 30 MLB Clubs, based in 17 states throughout the
United States (with one Club located in Canada). The MLB
        SENNE V. KANSAS CITY ROYALS BASEBALL                67

Clubs employ around 6,000 minor league players. Each of
these players signs a Uniform Player Contract, which
governs the employment relationship between the player and
an MLB Club. The Uniform Player Contract contains a New
York choice-of-law provision.

    Each MLB Club is associated with at least six minor
league affiliate teams; most Clubs have seven or eight.
Minor league affiliate teams are loose associations or
groups, rather than corporate entities; they do not function as
employers. The minor league teams are located in one of 44
different states.

    Each spring, each Major League Club sends its minor
league players to spring training in either Arizona or Florida.
Following spring training, the Club assigns selected
employee-players to play on one or more of its minor league
affiliate teams. Employees who are not selected to play on
an affiliate team remain at the Arizona or Florida facilities
for extended spring training. The Clubs reassign their
employee-players to different minor league affiliate teams
throughout the five-month championship season, sometimes
playing on a minor league team for only a single game.

    During each championship season, the affiliate minor
league teams play against other teams in one of several
minor leagues. One of these minor leagues, the California
League, is comprised of eight to ten minor league affiliate
teams. During the 2010 through the 2015 championship
seasons, a total of 2,113 minor league players were assigned
to play for affiliate teams in the California League. While
the California League plays its championship season games
only in California, the players participating in the California
League are employees of MLB Clubs located in one of six
different states: California, Arizona, Ohio, Colorado,
Washington, or Texas. Several of the plaintiffs in this appeal
68      SENNE V. KANSAS CITY ROYALS BASEBALL

who played in the California League during the
championship season worked for MLB Clubs located
outside of California. For example, Ryan Kiel, who played
in the California League on the Bakersfield Braves during
part of the 2012 championship season, is a resident of
Florida and an employee of the Cincinnati Reds, a Club
headquartered in Cincinnati, Ohio. Brad McAtee, a New
York resident and another representative of the California
class, worked for the Colorado Rockies, a club
headquartered in Denver, Colorado; he trained or played in
Washington, Arizona, California, and New York. And
another California class representative, Mitch Hilligoss,
resides in Illinois and was employed by both the New York
Yankees and the Texas Rangers. He played not only in
California, but also in Arizona, Texas, and South Carolina
during the 2010 and 2011 seasons. In short, the potentially
affected jurisdictions include: (1) Arizona and Florida,
where the employees trained for varying lengths of time; (2)
the states in which the players reside, which includes at least
19 states (only accounting for the 61 class representatives);
and (3) the states in which the players’ employers (the 22
MLB Clubs) are located. Because the employees argue that
MLB (headquartered in New York) is also an employer, and
because the Uniform Player Contract provides that the laws
of New York apply to any dispute under the contract, New
York minimum wage and overtime law is likewise
applicable.

    Plaintiffs initially sought certification of eight classes
under Federal Rule of Procedure 23(b)(3): a California
class, a Florida class, an Arizona class, a North Carolina
class, a New York class, a Pennsylvania class, a Maryland
class, and an Oregon class. The district court declined to
certify the plaintiffs’ proposed classes, in part because they
presented significant choice-of-law problems that could not
          SENNE V. KANSAS CITY ROYALS BASEBALL                         69

be handled on a classwide basis. The plaintiffs then moved
for reconsideration, narrowing the proposed classes to the
Florida and Arizona classes, 1 and the California class. 2 The
proposed Arizona class consists of players who are
employees of Major League Baseball Clubs located in 14
states, who are residents of at least 13 states (only accounting
for the 25 class representatives), and who were assigned to
spring training in Arizona for four weeks or more. The
proposed Florida class consists of players who are
employees of Major League Baseball Clubs located in 17
states, who are residents of at least 13 states (only accounting
for the 29 class representatives), and who were assigned to
spring training in Florida for four weeks or more. The
proposed California class consists of 2,113 players who are
employees of the 11 Major League Baseball Clubs that had
affiliate teams in the California League during the 2010
through 2015 championship seasons, who are residents of at
least 11 states (only accounting for the named class
representatives), and who played on an affiliate team in the
California League during the 2010 through 2015
championship seasons.



    1
       The Florida and Arizona classes were defined (respectively) as
including “[a]ny person who, while signed to a Minor League Uniform
Player Contract, participated in spring training, instructional leagues, or
extended spring training in [Florida or Arizona] on or after Feb 7, 2009,
and had not signed a Major League Uniform Player Contract before
then.”

    2
      The California class was defined as “[a]ny person who, while
signed to a Minor League Uniform Player Contract, participated in the
California League on or after February 7, 2010, and had not signed a
Major League Uniform Player Contract before then.”
70           SENNE V. KANSAS CITY ROYALS BASEBALL

    The district court declined to certify a Florida class and
an Arizona class of plaintiffs under Rule 23(b)(3) of the
Federal Rules of Civil Procedure. 3 It held that under
California choice-of-law principles, the problems that would
have to be navigated in order to adjudicate the claims of the
Florida and Arizona classes presented significant
individualized issues that could not be handled on a
classwide basis. We review this determination for abuse of


     3
         Rule 23(b)(3) provides that:

            A class action may be maintained if Rule 23(a) is
            satisfied and if: . . .

                (3) the court finds that the questions of law or fact
                common to class members predominate over any
                questions affecting only individual members, and
                that a class action is superior to other available
                methods for fairly and efficiently adjudicating the
                controversy. The matters pertinent to these
                findings include:

                (A) the class members’ interests in individually
                controlling the prosecution or defense of separate
                actions;

                (B) the extent and nature of any litigation
                concerning the controversy already begun by or
                against class members;

                (C) the desirability or undesirability of
                concentrating the litigation of the claims in the
                particular forum; and

                (D) the likely difficulties in managing a class
                action.

Fed. R. Civ. Proc. 23(b)(3).
        SENNE V. KANSAS CITY ROYALS BASEBALL                71

discretion. Abdullah v. U.S. Sec. Assocs., 731 F.3d 952, 956
(9th Cir. 2013).

                              II

    A brief summary of the legal framework for deciding
whether choice-of-law issues preclude certifying a class
under Rule 23(b)(3) is helpful here. In short, before
certifying a class under this provision, the court must find
“that the questions of law or fact common to class members
predominate over any questions affecting only individual
members.” Fed. R. Civ. P. 23(b)(3). When the plaintiffs
bring a class action involving multiple jurisdictions, a court
must consider the impact of potentially varying state laws.
See Zinser v. Accufix Research Inst., Inc., 253 F.3d 1180,
1188–89 (9th Cir. 2001). If the forum state’s substantive law
may be constitutionally applied to parties in other states, the
district court must apply the forum state’s choice-of-law
rules to determine which laws apply. See Mazza v. Am.
Honda Motor Co., 666 F.3d 581, 589–90 (9th Cir. 2012).
After applying the forum state’s choice-of-law rules, if the
district court determines that the laws of only one state
apply, then variations in state law do not raise a barrier to
class certification. See id. at 590–91. But if the plaintiffs’
claims must be adjudicated under the laws of multiple
jurisdictions, the district court will have to determine
whether the complexities and managerial problems defeat
predominance. See Zinser, 253 F.3d at 1188–89.

   The forum state here is California, and thus California’s
choice-of-law rules apply. A brief dive into the history of
California’s choice-of-law jurisprudence indicates that
California has long rejected the approach that the majority
now adopts.
72       SENNE V. KANSAS CITY ROYALS BASEBALL

    In the first half of the twentieth century, California courts
agreed that it was “the settled law in the United States that
an action in tort is governed by the law of the jurisdiction
where the tort was committed.” Loranger v. Nadeau, 215
Cal. 362, 364–66 (1932), overruled in part by Reich v.
Purcell, 67 Cal. 2d 551 (1967). California courts would
therefore generally “determine the substantive matters
inherent in the cause of action by adopting as their own the
law of the place where the tortious acts occurred, unless it
[was] contrary to the public policy of” California. Grant v.
McAuliffe, 41 Cal. 2d 859, 862 (1953). This typical
approach was reflected in the Restatement (First) of the
Conflict of Laws. See Restatement (First) of Conflict of
Laws § 377 (1934) (applying the law of “[t]he place of the
wrong”). California courts “assumed that the law of the
place of the wrong created the cause of action and
necessarily determined the extent of the liability.” Reich, 67
Cal. 2d at 553. Therefore, when the injury at issue occurred
in California, courts would generally apply California law.
See Loranger, 215 Cal. at 364–66.

    But this approach came under fire for being an inflexible
and mechanical rule. See Travelers Ins. Co. v. Workmen’s
Comp. Appeals Bd., 68 Cal. 2d 7, 14 n.6 (1967). Moreover,
“[i]n a complex situation involving multi-state contacts,”
California courts realized that “no single state alone can be
deemed to create exclusively governing rights.” Reich, 67
Cal. 2d at 553. In response, California courts began adopting
a more flexible approach. See, e.g., id.; Hurtado v. Super.
Ct. of Sacramento Cty., 11 Cal. 3d 574, 581–82 (1974). In a
“landmark opinion . . . for a unanimous court in Reich v.
Purcell,” the California Supreme Court “renounced the prior
rule, adhered to by courts for many years, that in tort actions
the law of the place of the wrong was the applicable law in a
California forum regardless of the issues before the court.”
        SENNE V. KANSAS CITY ROYALS BASEBALL                 73

Hurtado, 11 Cal. 3d at 579. Instead, California concluded
that each state’s interest in applying its own law must be
evaluated. See id. In 1971, the Restatement (Second) of
Conflict of Laws reflected the general movement away from
the law-of-the-situs approach espoused by the First
Restatement by replacing it with a more flexible approach
that considered each state’s interest in applying its own laws.
See Restatement (Second) of Conflict of Laws § 6 (1971);
see also id. introduction (describing the revised approach as
an “enormous change” from the “rigid rules” laid out in the
First Restatement). California courts described the new
approach to choice-of-law principles, which reflected the
approach of the Second Restatement, as a “governmental
interest approach” that required consideration of the interests
of all the involved states. See, e.g., Dixon Mobile Homes,
Inc. v. Walters, 48 Cal. App. 3d 964, 972 (1975). In Offshore
Rental Co. v. Continental Oil Co., the California Supreme
Court definitively announced that “[q]uestions of choice of
law are determined in California . . . by the ‘governmental
interest analysis,’” which requires the court to “search to find
the proper law to apply based upon the interests of the
litigants and the involved states.” 22 Cal. 3d 157, 161
(1978).

    Today, California courts no longer apply “the old choice-
of-law rule that generally called for application of the law of
the jurisdiction in which a defendant’s allegedly tortious
conduct occurred without regard to the nature of the issue
that was before the court.” McCann v. Foster Wheeler LLC,
48 Cal. 4th 68, 97 (2010) (emphasis in original). Instead,
California courts apply the three-step governmental interest
test. Hairu Chen v. Los Angeles Truck Ctrs., LLC, No.
S240245, 2019 WL 3281346, at *3 (Cal. July 22, 2019).
“First, the court determines whether the relevant law of each
of the potentially affected jurisdictions with regard to the
74       SENNE V. KANSAS CITY ROYALS BASEBALL

particular issue in question is the same or different.” Id.
(internal quotation marks omitted). If there is a difference,
“the court examines each jurisdiction’s interest in the
application of its own law under the circumstances of the
particular case to determine whether a true conflict exists.”
Id. (internal quotation marks omitted). As the final step, “if
the court finds that there is a true conflict, it carefully
evaluates and compares the nature and strength of the
interest of each jurisdiction in the application of its own law
to determine which state’s interest would be more impaired
if its policy were subordinated to the policy of the other state,
and then ultimately applies the law of the state whose interest
would be the more impaired if its law were not applied.” Id.
(cleaned up).

    Although California choice-of-law cases “continue to
recognize that a jurisdiction ordinarily has the predominant
interest in regulating conduct that occurs within its borders,”
see McCann, 48 Cal. 4th at 97–98 (internal quotation marks
omitted), California courts have not relied on this general
principle to shortcut the required three-part analysis, see,
e.g., Sullivan, 51 Cal. 4th at 1202. Indeed, in McCann, a
case on which the majority relies for its rule, Maj. Op. at 30–
31, the California Supreme Court walked through each of the
steps of the governmental interest analysis to determine
whether to apply the law of Oklahoma (where the tort
occurred) or California (where the plaintiff resided). 48 Cal.
4th at 96–98. Only after determining at the second step that
“each state has an interest in having its law applied under the
circumstances of the present case,” id. at 96, did the court
proceed to the third step and determine that Oklahoma law
applied, in part because “a failure to apply California law on
the facts of the present case will effect a far less significant
impairment of California’s interest,” id. at 99 (emphasis
added). In short, as the California Supreme Court recently
          SENNE V. KANSAS CITY ROYALS BASEBALL                        75

explained, “the governmental interest test is far from a
mechanical or rote application of various factors,” Hairu
Chen, 2019 WL 3281346, at *5, and California courts must
scrupulously apply each step of the three-step test. 4

    California courts also apply the governmental interest
analysis in cases where plaintiffs and defendants raise
choice-of-law issues, even outside the tort context. In
Sullivan, the California Supreme Court applied the
governmental interest analysis to a wage-and-hour dispute,
in a case where plaintiffs contended California’s overtime
law governed their work in California, and the defendant
contended the laws of plaintiffs’ home states governed. 51
Cal. 4th at 1202. Sullivan did not merely apply California’s
overtime law, although California was the site where the
work occurred. See id. As explained below, Sullivan made
a detailed analysis of each of the three steps of the
governmental interest test. See id.

    At the same time as California courts were migrating
towards the multifaceted governmental interest test
espoused by the Second Restatement, California courts also
adopted the Second Restatement’s approach to contractual
choice of law provisions. See Gamer v. duPont Glore
Forgan, Inc., 65 Cal. App. 3d 280, 287–88 (1976). Under
this test, courts would generally defer to the law of the state
chosen by the parties unless either “the chosen state has no
substantial relationship to the parties or the transaction and

    4
      Indeed, in the California class action context, the California
Supreme Court has made clear there are no presumptive choice-of-law
rules. Rather, a “trial court cannot reach an informed decision on
predominance and manageability without first determining whether class
claims will require adjudication under the laws of other jurisdictions and
then evaluating the resulting complexity where those laws must be
applied.” Hairu Chen, 2019 WL 3281346, at *5.
76      SENNE V. KANSAS CITY ROYALS BASEBALL

there is no other reasonable basis for the parties choice, or
. . . application of the law of the chosen state would be
contrary to a fundamental policy of a state which has a
materially greater interest than the chosen state in the
determination of the particular issue and which . . . would be
the state of the applicable law in the absence of an effective
choice of law by the parties.” Nedlloyd Lines B.V. v. Super.
Ct. of San Mateo Cty., 3 Cal. 4th 459, 465 (1992).

    In undertaking the predominance analysis under Rule
23(b), the court is required to consider the full scope of
California’s choice-of-law framework, including each
state’s interest in applying its own law, as well as the
contractual choice-of-law provision. See Mazza, 666 F.3d at
590–91. If individualized choice-of-law inquiries swamp
predominance, then the class cannot be certified. See id.

                              III

    In addressing the choice-of-law framework in the
context of a Rule 23(b) inquiry, the majority concedes that
the differences in state law involved in this case are material.
Maj. Op. at 29–30. But instead of undertaking California’s
choice-of-law analysis by identifying the relevant laws of
each potentially affected jurisdiction and examining each
jurisdiction’s interest in the application of its own law, the
majority sidesteps this analysis entirely by relying solely on
its general rule that the jurisdiction where an employee’s
work occurs has the predominant interest in regulating
conduct that occurs within its borders. Maj. Op. at 30–35.
Not only is this approach contrary to substantive California
law, but the majority’s justification of this approach on
practical grounds is entirely misguided.
          SENNE V. KANSAS CITY ROYALS BASEBALL                      77

                                  A

     First, as the above description of California law makes
clear, the majority misreads and misapplies substantive
California law. In considering whether the district court
erred in declining to certify the Arizona and Florida classes,
the majority interprets California’s choice-of-law rules as
establishing the general principle that California has the
predominant interest in regulating conduct occurring within
its borders. Maj. Op. at 31. In this vein, the majority asserts
that Sullivan “strongly militates” against concluding that any
other state has an interest in wage and hour laws that “would
be adequate to overcome the presumption that the state in
which the conduct at issue occurs has the ‘predominant
interest’ in applying their own law.” Maj. Op. at 37. These
conclusions are wrong in two different ways.

    Most important, the majority misreads California’s
choice-of-law rules to conclude that the law of the situs
where the work took place controls. This is clearly contrary
to California law: as shown above, California courts have
expressly rejected the blanket rule that the law of the situs
applies, Travelers, 68 Cal. 2d at 11, and “when application
of the law of the place of the wrong would defeat the
interests of the litigants and of the states concerned,” they do
not apply that law. Reich, 67 Cal. 2d at 554; see also
Berhard v. Harrah’s Club, 16 Cal. 3d 313, 316, 323 (1976)
(applying California law where the tort occurred in Nevada
but the harm was felt in California). 5 Even where, as here, a

    5
      The majority also errs in applying substantive California law to
determine Arizona’s and Florida’s interests in the application of their
own laws, the second step of California’s governmental interest test.
Maj. Op. at 30–32. In other words, because the California Supreme
Court has expressed a strong interest in regulating wage and hour claims
78        SENNE V. KANSAS CITY ROYALS BASEBALL

contractual choice-of-law provision is involved, California
applies the law of the parties’ choosing only after
considering the relevant state interests. See Nedlloyd, 3 Cal.
4th at 465. For example, in Washington Mutual Bank, FA v.
Superior Court, the California Supreme Court analyzed a
state class action that involved both a contractual choice-of-
law provision and the applicability of the governmental
interest test. 24 Cal. 4th 906, 915 (2001). The court
determined that the test from the Restatement (Second) of
Conflict of Laws under Nedlloyd applied to the class action,
id. at 918, and that if the choice-of-law provision did not
apply under Nedlloyd, the court must undertake the
governmental interest analysis, id. at 919–21.

    Second, in the context of wage-and-hour disputes, the
majority wildly overreads Sullivan. In Sullivan, the
California Supreme Court expressly limited its ruling to the
situation before it: the state’s interest in applying California
labor law to nonresident employees working for a California
employer. Sullivan, 51 Cal. 4th at 1194–95. The court was
careful not to address any other scenario. See id. Therefore,
the majority’s extension of Sullivan to establish a general
rule that California has a superior interest in applying its law
to wage-and-hour claims that arise within its borders, Maj.
Op. at 37–38, (let alone generalizing the majority’s

within its borders, the majority assumes that Arizona and Florida have
the exact same interest. To support this assumption, the majority cites
California cases which determined—after the application of the
governmental interest test—that a particular foreign state had a superior
interest in having its law applied. The majority fails to identify any
Arizona or Florida opinion expressing such an interest, however. This
is clearly wrong. Although the district court is bound to apply the choice-
of-law provisions of California (the forum state), the district court may
not impute California’s interest in regulating conduct within its borders
to Arizona and Florida.
        SENNE V. KANSAS CITY ROYALS BASEBALL               79

extrapolation of California’s rule to all other states) is not
supported by Sullivan.

    A brief description of Sullivan reveals the majority’s
error. In Sullivan, the California Supreme Court responded
to a certified question regarding whether California labor
law applied to nonresident employees who worked both in
California and in other states for a California-based
employer. 51 Cal. 4th at 1194. The employees at issue
worked as instructors for Oracle Corporation, a large
California-based company. Id. at 1194–95. Two of the
employees were residents of Colorado; while they worked
primarily in Colorado, they were required to travel and work
in other states, including California. Id. at 1195. A third
employee was an Arizona resident, but worked 20 days in
California. Id. Oracle did not pay these employees overtime
on the ground that they were exempt under California and
federal overtime laws as instructors. Id. The employees
sued Oracle, seeking unpaid overtime compensation. Id.
The question certified to the California Supreme Court was
whether California overtime law applied to the employees’
work in California. Id. at 1196.

    In its response to the certified question, the California
Supreme Court addressed two distinct inquiries: first,
whether, as a matter of statutory construction, the California
Labor Code’s overtime provisions applied to work
performed in California by nonresidents, id. at 1196–97, and
second, whether California’s choice-of-law principles
directed the court to apply the California Labor Code to the
plaintiffs, id. at 1202–06. Sullivan focused on the question
whether a California employer had to pay its employees
under California’s overtime law or under the overtime law
of the state where the employees resided during the period
when the employees worked in California. See id. at 1196.
80      SENNE V. KANSAS CITY ROYALS BASEBALL

Because the employer in that case was Oracle, a resident of
California, the court did not have to consider whether the
overtime law of the state of a nonresident employer (the
issue in our case) might apply.

    Sullivan first made a point of carefully examining
California’s overtime statute to ensure it applied to
nonresident employees of a California employer. Id. at
1197. The court noted that the plain text of the applicable
overtime statute stated that the statute applied to “all
individuals,” which would include residents and
nonresidents alike. Id. It also noted that the legislature knew
how to exclude nonresidents when it wanted to do so,
because it had expressly exempted some out-of-state
employers from complying with workers’ compensation
provisions. Id. Therefore, Sullivan held the overtime statute
would apply to the plaintiffs in the case before it.

    Because the statute was potentially applicable to
nonresidents by its terms, the California Supreme Court then
applied California’s three-step governmental interest test to
determine which state’s law applied. Id. at 1202–03.
Sullivan first asked whether the overtime law of California
was the same or different than the overtime laws of Colorado
and Arizona, where the employees resided. Id. at 1203. The
court determined that the laws were different. Id. Federal
overtime law applied in Arizona, and federal law required
less overtime compensation than California. Id. Colorado
overtime law applied in Colorado, but it too required less
compensation than California. Id.

    Sullivan next examined “each jurisdiction’s interest in
the application of its own law under the circumstances of the
particular case to determine whether a true conflict exists.”
Id. at 1203. Relying on the California statute and case law,
Sullivan first noted that “California has, and has
         SENNE V. KANSAS CITY ROYALS BASEBALL                 81

unambiguously asserted, a strong interest in applying its
overtime law to all nonexempt workers, and all work
performed, within its borders.” Id. Arizona had no overtime
law, and Colorado’s statute expressly did not apply out of
state, so the court found that neither Arizona nor Colorado
had “asserted an interest in regulating overtime work
performed in other states.” Id. at 1204. Therefore, there was
no true conflict. See id. The court acknowledged, however,
that states could have an interest in the extraterritorial
application of their employment laws under certain limited
circumstances. See id. at 1199.

     The final step in the governmental interest analysis was
to determine which state’s interest would be more impaired
if its policy were subordinated to the policy of the other state.
See id. at 1205–06. The court concluded that California’s
interests would be more impaired if nonresidents employed
in California were covered only by the law of the
nonresident’s state. Id. Among other considerations,
Sullivan reasoned that adopting a different rule might
encourage California employers to hire nonresidents of
California to work in California. Id. at 1206. By contrast,
Colorado and Arizona had no interest in applying their
overtime laws to their residents working in California. See
id.

    Sullivan therefore concluded that California’s overtime
law “does apply to overtime work performed in California
for a California-based employer by out-of-state plaintiffs in
the circumstances of this case.” Id. The court did not
address whether the same rule would apply for a nonresident
employer.

    Contrary to the majority’s conclusion, Sullivan did not
establish a rule that every California wage-and-hour law
applies to all persons working in California regardless of
82       SENNE V. KANSAS CITY ROYALS BASEBALL

their state of residence or their employer’s state of residence.
To the contrary, rather than enunciate such a rule, Sullivan
carefully analyzed the law and policy of each relevant
jurisdiction, consistent with California’s governmental
interest test. See id. at 1202–06. Sullivan expressly limited
its analysis to the particular facts of the case before it: a case
involving California overtime law, a California employer,
and employees residing in Arizona and Colorado. See id.
Sullivan specified that it was not applying its rule to out-of-
state employers, as is the case here. Id. at 1201 (noting that
the court did not need to address “the asserted burdens on
out-of-state businesses to which Oracle refers,” in part
because “no out-of-state employer is a party to this
litigation[, and] Oracle itself is based in California”).
Further, Sullivan clarified that its holding did not apply to
any California labor law other than the overtime law,
explaining, “[w]hile we conclude the applicable conflict-of-
laws analysis does require us to apply California’s overtime
law to full days and weeks of work performed here by
nonresidents one cannot necessarily assume the same result
would obtain for any other aspect of wage law.” Id. at 1201
(citation omitted). Indeed, “California’s interest in the
content of an out-of-state business’s pay stubs, or the
treatment of its employees’ vacation time, for example, may
or may not be sufficient to justify choosing California law
over the conflicting law of the employer’s home state.” Id.

     Moreover, Sullivan acknowledged that different
outcomes could result under different circumstances. By
beginning its analysis with the statutory language, Sullivan
indicated that the state legislature could decide not to apply
its employment laws to some employees who work in-state,
id. at 1197 (conducting statutory analysis to confirm that the
California overtime legislation applied to “any individual”),
or could exempt out-of-state employers who send employees
        SENNE V. KANSAS CITY ROYALS BASEBALL                 83

into California from complying with California law, as it did
in the case of workers’ compensation law, id., or could
choose not to apply overtime law to employees who reside
out of state, id. at 1198. Similarly, Sullivan acknowledged
that a truck driver employee based at a Washington facility
of a California employer could be entitled to overtime
compensation under Washington law for the time he spent
driving outside the state. See id. at 1200, 1204.

    In fact, Sullivan expressly rejected the arguments that it
was adopting a general rule that California’s employment
laws applied in all contexts, holding instead that disputes in
each different context would be “resolved under the
applicable conflict of laws analysis.” Id. at 1200. “In any
event,” the court explained, “to the extent other states have
legitimate interests in applying their own wage laws to their
own residents for work performed in California, the
applicable conflict-of-laws analysis takes those interests into
account.” Id. at 1202. In other words, Sullivan rejected the
very approach that the majority now adopts, and instead,
Sullivan stands for the proposition that the determination of
which state’s law applies requires a careful analysis of each
relevant state’s law and policies.

                               B

    Second, the majority’s argument that practical
considerations compel the adoption of a general rule has the
situation entirely backwards.

     The only practical consideration flagged by the majority
is that, absent a rule that the hours and wage laws of the situs
always apply to workers within its borders, Maj. Op. at 35–
36, employers would be required to properly ascertain the
residency status of each of its employees, to track applicable
state laws, and to determine which law applies, Maj. Op. at
84      SENNE V. KANSAS CITY ROYALS BASEBALL

27–28. Such a concern does not arise if the state law at issue
merely requires a resident employer to pay each of its
employees according to the resident state’s laws, even when
the employee is working temporarily in another state. In
other words, if an MLB Club in Ohio paid each of its player–
employees pursuant to Ohio overtime law, the MLB Club
would have no extra burden at all. Unlike Sullivan, the
majority fails to recognize that states may enact many
different types of laws, and that conflicts between state laws
can be resolved through the application of choice-of-law
rules. Cf. Sullivan, 51 Cal. 4th at 1201–02.

    On the other hand, the rule the majority establishes today
could have dire consequences for employers and employees.
For example, a rule requiring that the law of the situs always
applies would require employers to research and comply
with various states’ laws whenever their employees traveled
for short conferences or business meetings. An employer
would have to research applicable state law whenever an
employee traveled across state lines, including when an
employee was in transit. Presumably, when an employee
traveled across state lines by car or airplane, the employer
would need to track the amount of time the employee spent
in each state during travel in order to comply with this rule.
Such a rule would make it difficult for employers to
compensate interstate truck drivers or traveling salespersons.
Moreover, the majority’s rule would also burden employees
who would no longer be protected by the laws of their
resident state or employer’s state while traveling for work,
forcing the employees to earn less money for work travel.
Rather than adopting a rule that the law of the situs applies,
the better solution is faithfully adhering to long-established
choice-of-law principles, which resolve the issue in a
reasonable and time-tested way.
        SENNE V. KANSAS CITY ROYALS BASEBALL                 85

                              IV

    Because it is not possible to derive a general rule from
Sullivan, and California’s choice-of-law rules weigh against
any such rule, the majority should have considered the
applicability of California’s choice-of-law rules to the
plaintiffs’ claims.

    Given that a minimum of 22 states potentially have an
interest in applying their wage and hour laws, and that (as
the majority concedes) there are material differences
between the states, applying California’s three-step
governmental interest test would be a significant task.

    First, as a threshold matter, the court must analyze the
contractual choice-of-law provision (i.e., New York) in the
governmental law analysis under Nedlloyd, 3 Cal. 4th at 466,
and the Restatement (Second) of Conflict of Laws. This
would require the court to analyze whether New York law
has a substantial relationship to the parties or transactions
here and whether application of New York law would be
contrary to Arizona’s or Florida’s interests. See id. at 465.

    Second, if the contractual choice-of-law provision does
not govern, a court applying Sullivan would first have to
determine whether the minimum wage laws and overtime
laws of Arizona and Florida apply by their terms to
nonresident employees who work for nonresident
employers, Sullivan, 51 Cal. 4th at 1202–03. Assuming the
laws did apply, the court would then have to identify the
relevant laws of each of the potentially affected jurisdictions.
See id. at 1203. It would then have to determine whether
there is a conflict between the laws of Arizona and Florida,
on the one hand, and the laws of the different states in which
the employees and employers reside. See id.
86        SENNE V. KANSAS CITY ROYALS BASEBALL

     If there is a true conflict, then the court would have to
compare the nature and strength of each jurisdiction’s
interest in the application of its own law to determine
whether a true conflict exists under the circumstances of the
particular case. See id. at 1203–05. Contrary to the majority,
Maj. Op. at 34–35, other states have an interest in applying
their wage and hour laws outside their borders. For example,
the Boston Red Sox is an MLB Club headquartered in
Boston, Massachusetts, and a franchise defendant in this
lawsuit. Massachusetts has previously applied its wage-and-
hour laws extraterritorially. See Dow v. Casale, 989 N.E. 2d
909 (Mass. App. Ct. 2013). Moreover, MLB Clubs in
Illinois, Pennsylvania, New York, and Washington are also
defendants in this proposed class action, and courts have
applied wage-and-hour laws in those states extraterritorially.
See Baxi v. Ennis Knupp & Assocs., Inc., No. 10-cv-6346,
2011 WL 3898034, at *14–15 (N.D. Ill. Sept. 2, 2011);
Truman v. DeWolff, Boberg & Assocs., No. 07-cv-1702,
2009 WL 2015126, at *2 (W.D. Pa. July 7, 2009); Friedrich
v. U.S. Comput. Sys., Inc., No. 90-cv-1615, 1996 WL 32888,
at *8 (E.D. Pa. Jan. 22, 1996); Pierre v. Gts Holdings, Inc.,
No. 15-cv-143, 2015 WL 7736552, at *1, *5 (S.D.N.Y. Nov.
30, 2015); Bostain v. Food Express, Inc., 159 Wash.2d 700,
709–711 (Wash. 2007) (en banc). 6

    It is not surprising that the district court determined that
this type of analysis would defeat the predominance that
Rule 23(b)(3) requires.          No two player-employees’

     6
       The majority notes that, in many cases, state “courts have looked
closely at where the relevant work is performed” to determine whether
to apply the state’s laws extraterritorially. Maj. Op. at 35 n.13.
Certainly, state courts look to where the work is performed as one factor
to determine which state’s law applies. The majority errs by concluding
that where the work is performed is effectively the only relevant factor
in the choice-of-law analysis.
        SENNE V. KANSAS CITY ROYALS BASEBALL                87

circumstances are alike; the players hail from at least 19
resident states, worked for one or more MLB Clubs based in
one of 22 states for varying lengths of time, and played on
one or more minor league affiliate teams in an assortment of
states for as little as one day or as long as an entire season.
Sullivan and California’s choice-of-law analysis require the
court to consider all of the relevant states’ laws and weigh
the commensurate state interests in applying those laws. The
highly individualized nature of the choice-of-law inquiry
with respect to each player could swamp the predominance
required for certification under Rule 23(b)(3). See Hanlon
v. Chrysler Corp., 150 F.3d 1011, 1022 (9th Cir. 1998);
Wash. Mut. Bank, FA, 24 Cal. 4th at 922. In any event, the
district court did not abuse its discretion by refusing to
certify the Florida and Arizona classes.

    For the same reason, the district court erred in certifying
the California class without completing its choice-of-law
analysis. Sullivan’s conclusion does not control where the
relevant employer is not a California-based employer. 51
Cal. 4th at 1197–98. While Sullivan held that California’s
overtime laws apply to employees of a California employer
who are residents of Arizona and Colorado but work
occasionally in California, Sullivan did not address the
application of both overtime and minimum wage laws to
employees of out-of-state employers who work occasionally
in California. Id. at 1197–98. Instead, Sullivan requires a
court to apply the three-part governmental interest analysis,
including weighing the interests of the employees’ and
employers’ resident states in applying their own laws. Id. at
1202–03.

    Here, more than half of the MLB Clubs with minor
league affiliates that play in the California League are out-
of-state employers. Moreover, the plaintiffs argue that the
88      SENNE V. KANSAS CITY ROYALS BASEBALL

MLB, a New York-based entity, is also an employer. The
players themselves hail from at least 11 states, even if only
the 26 class representatives named in this lawsuit were
included in the class. In addition, 68.7% to 74.7% of the
players who were assigned to a minor league affiliate in the
California League also played as a member of a minor league
affiliate in a different state during the 2010 to 2015
championship seasons. Approximately 11% of the proposed
class members from the 2010 championship season were
assigned to an affiliate in the California League for one week
or less. Sullivan requires that the court weigh each relevant
jurisdiction’s interest in applying its laws, including all of
the relevant variables: whether the players are employed by
an out-of-state MLB Club; whether the players are
nonresidents of California; whether the players spent only a
short time in California; whether any other state’s law might
apply; and whether that state’s interest in applying its own
law outweighs California’s interest. See 51 Cal. 4th at 1202–
03. Because the choice-of-law inquiries cannot be neatly
solved with a law-of-the-situs rule as the majority suggests,
individual choice-of-law issues also appear to defeat
predominance for the California class.

                              V

    No doubt the analysis of the intersection between Rule
23(b)(3)’s predominance inquiry and California’s choice-of-
law inquiry is multilayered and complex, particularly in a
case like this one, involving different types of wage and hour
claims, employers residing in multiple states, employees
residing in multiple states, and three states where work was
performed. But the majority errs in attempting to sidestep
the analysis entirely in one fell swoop by the simple
expedient of declaring that each jurisdiction generally has a
predominant interest in regulating conduct that occurs within
         SENNE V. KANSAS CITY ROYALS BASEBALL                  89

its borders, a conclusion that is contrary to the requirement
that California courts undertake the governmental interest
analysis in every case. Although the majority gives lip
service to the possibility of exceptions to this rule, its failure
to consider all the variables in this case to determine whether
any exception was applicable here gives the lie to such
claimed flexibility. Because the majority’s conclusion that
courts can sidestep a choice-of-law analysis by relying on a
general rule is contrary to our precedents, and because it will
impose burdens on employers and disadvantage employees
in many circumstances, I dissent.
