                                                                           F IL E D
                                                                     United States Court of Appeals
                                                                             Tenth Circuit
                                         PUBLISH
                                                                           August 7, 2006
                      U N IT E D ST A T E S C O U R T O F A PP E A L S
                                                                         Elisabeth A. Shumaker
                                                                             Clerk of Court
                                    T E N T H C IR C U IT



K A RLA CA RPEN TER ; LIN D A
W ILK ERSO N ; SH ER YL LA N DON;
SA N D Y WILC YN SK I; SO N Y A
PH ILLIPS; C HA RLEN E C HA PM AN;
C HERYL LEE PER SIN G ER ; NENA
H O LD ER ; R UB Y R YH ER D,
individually & on behalf of all others
sim ilarly situated; M A RY D EA N;
FA ITH BR ID G EWA T ER ; V ERLENE
M AHOLM ES, individually,

       Plaintiffs - Appellants/Cross-
       Appellees,


v.                                                 Nos. 04-3334, 04-3350, 04-3351


TH E BOEIN G CO M PA N Y ,

       Defendant - Appellee/Cross-
       Appellant.

--------------------------------------

K A RLA CA RPEN TER ; LIN D A
W ILK ERSO N ; SH ER YL LA N DON;
SA N D Y WILC YN SK I; SO N Y A
PH ILLIPS; C HA RLEN E C HA PM AN;
C HERYL LEE PER SIN G ER ; NENA
H O LD ER ; R UB Y R YH ER D,
individually, and on behalf of all other
persons similarly situated,

       Petitioners,
                                                           No. 04-602
 v.

 TH E B OEIN G CO M PA N Y ,

       Respondent.




        A PPE A L S FR O M T H E U N IT ED ST A T ES D IST R IC T C O U R T
                      FO R T H E D IST R IC T O F K A N SA S
                         (D .C . N O . 02-C V -1019-W E B )


Jeffrey T. Sprung, Hagens Berman Sobol Shapiro LLP, argued for Plaintiffs -
Appellants/Cross-Appellees, (Steve W . Berman, Andrew M . Volk, Ivy D. Arai,
Hagens Berman Sobol Shapiro LLP, Seattle, W ashington, and M ark B. Hutton and
Derek S. Casey, Hutton & Hutton, W ichita, Kansas, with him on the brief).

James M . Armstrong, Foulston Siefkin LLP, argued for D efendant -
Appellee/Cross-Appellant, (M ary Kathleen Babcock, Trisha A. Thelen, Carolyn L.
M atthews, Foulston Siefkin LLP, W ichita, Kansas, and C. Geoffrey W eirich,
Paul, Hastings, Janofsky & W alker LLP, Atlanta, Georgia, with him on the brief).

M ary Dean, Faith Bridgewater and V erlene M aholmes, pro se Plaintiffs -
Appellants/Cross-Appellees, submitted a brief.


Before H A R T Z, A N D ER SO N , and O ’B R IE N , Circuit Judges.


H A R T Z, Circuit Judge.


      Plaintiffs appeal from the district court’s disposition of the em ploym ent-

discrim ination claim s of female employees at the Boeing Com pany’s W ichita,

Kansas, facility. They have sought to bring class-action claim s alleging several

                                          -2-
unlawful employm ent practices under both disparate-im pact and disparate-

treatm ent theories of discrim ination. The two subclasses relevant to this appeal

are a subclass of hourly female workers (the Hourly Subclass) and a subclass of

salaried female workers (the Salaried Subclass). Before us now are both (1) the

district court’s sum m ary judgm ent on the Hourly Subclass’s disparate-im pact

claim relating to overtim e assignm ents, certified by the district court as a final

judgm ent under Fed. R. Civ. P. 54(b); and (2) several of the district court’s class-

certification decisions relating to both the Hourly and Salaried Subclasses, on

which we provisionally granted interlocutory appeal under Fed. R. Civ. P. 23(f).

Boeing has cross-appealed to challenge the district court’s class certification of

the Hourly Subclass’s disparate-im pact claim in the event that we reverse the

district court’s grant of sum m ary judgm ent on that claim .

      W e affirm the district court’s sum m ary judgm ent because Plaintiffs’

statistical evidence is not adequately based on data restricted to persons eligible

for overtime assignments. This affirmance moots the cross-appeal. Also, we

dism iss Plaintiffs’ appeal of the district court’s class-action decisions because

they were not filed within 10 days of the district court’s initial decision denying

class certification. Finally, we reject the claim s of three former class

representatives who were stripped of that designation by the district court on the

ground that they could not “fairly and adequately protect the interests of the

class,” Fed. R. Civ. P. 23(a)(4).

                                          -3-
I.    BACKGROUND

      Title VII of the Civil Rights Act of 1964 prohibits, am ong other things,

discrim ination on the basis of sex. See 42 U.S.C. § 2000e-2(a). Two types of

claim s are recognized under Title VII: disparate treatment and disparate im pact.

      “Disparate treatm ent” . . . is the most easily understood type of
      discrim ination. The em ployer sim ply treats some people less
      favorably than others because of their race, color, religion, sex, or
      national origin. Proof of discrim inatory m otive is critical, although
      it can in som e situations be inferred from the mere fact of differences
      in treatm ent. . . .
             Claim s of disparate treatm ent m ay be distinguished from
      claim s that stress “disparate im pact.” The latter involve employm ent
      practices that are facially neutral in their treatm ent of different
      groups but that in fact fall m ore harshly on one group than another
      and cannot be justified by business necessity. Proof of
      discrim inatory m otive . . . is not required under a disparate-im pact
      theory. Either theory m ay, of course, be applied to a particular set of
      facts.

Int’l Bhd. of Teamsters v. United States, 431 U.S. 324, 335 n.15 (1977) (citations

om itted). In a disparate-im pact claim the plaintiff is challenging an employm ent

practice that is “‘fair in form , but discrim inatory in operation.’” Bullington v.

United Air Lines, Inc., 186 F.3d 1301, 1312 (10th Cir. 1999) (quoting Griggs v.

Duke Power Co., 401 U.S. 424, 431 (1971), overruled on other grounds by Nat’l

R.R. Passenger Corp. v. M organ, 536 U.S. 101 (2002). “[A] plaintiff m ay

establish a prim a facie case of disparate im pact discrim ination by showing that a

specific identifiable em ploym ent practice or policy caused a significant disparate

im pact on a protected group.” Id. (internal quotation m arks om itted). This



                                          -4-
burden, which had been im posed by caselaw, see, e.g., Ortega v. Safeway Stores,

Inc., 943 F.2d 1230, 1242 (10th Cir. 1991), was codified by statute in 1991. See

42 U.S.C. § 2000e-2(k); Civil Rights Act of 1991, Pub. L. No. 102-166, § 105(a),

105 Stat. 1071, 1074-75. The 1991 statute departed from case law in several

respects, but none are relevant here.

      Discrim ination suits are often filed as putative class actions. W hether a

suit can proceed as a class action is governed by Fed. R. Civ. P. 23. Under that

rule the district court m ust determ ine “at an early practicable tim e,” Fed. R. Civ.

P. 23(c)(1)(A), whether a suit (or a particular claim within a suit) satisfies the

prerequisites of num erosity, comm onality, typicality, and adequacy of

representation, see id. 23(a), and falls within one of the categories of actions

m aintainable as class actions, see id. 23(b). W e review de novo whether the

district court applied the correct legal standard in its decision to grant or deny

class certification; when the district court has applied the proper standard, the

decision will be reversed only for abuse of discretion. See Shook v. El Paso

County, 386 F.3d 963, 967-68 (10th Cir. 2004). The district court can modify or

am end its class-certification determ ination at any time before final judgm ent in

response to changing circum stances in the case. See Fed. R. Civ. P. 23(c)(1)(C).

      In 2000, Plaintiffs, among others, filed a putative nation-wide class-action

suit in the United States District Court for the W estern District of W ashington,

alleging gender discrim ination in a variety of Boeing’s com pensation practices.

                                          -5-
The district court, however, certified only a class of female employees working at

Boeing’s W ashington facilities. In 2002 non-W ashington plaintiffs filed suits in

several states, including this suit in the District of Kansas.

      Boeing’s W ichita facility includes operations of three m ajor business units:

Boeing Com m ercial A irplanes, which is the largest group at the facility and is

responsible for comm ercial production; the W ichita Developm ent and

M odification Center, which is responsible for the site’s m ilitary business; and the

Shared Services G roup, which provides infrastructure support. According to the

com plaint, the W ichita facility is Boeing’s largest m anufacturing business. In

Decem ber 2001 Boeing had approximately 16,700 em ployees in K ansas.

      This appeal concerns Plaintiffs’ Title VII claim s alleging gender

discrim ination in Boeing’s com pensation and overtim e policies. Nine of the

Plaintiffs (the Carpenter Plaintiffs) seek to represent themselves and a class of

sim ilarly situated current and form er fem ale em ployees at Boeing’s W ichita

facility. The other three Plaintiffs (the D ean Plaintiffs) are mem bers of the class

but represent only them selves on appeal.

      The Hourly Subclass’s overtim e claim s were brought under both disparate-

im pact and disparate-treatm ent theories. The claim s are based on the allegation

that the discretion given to supervisors in assigning overtim e resulted in wom en

receiving consistently fewer overtim e assignm ents than their m ale counterparts.

In their disparate-treatm ent claim , they allege further that Boeing’s failure to act

                                          -6-
upon knowledge of the denial of those assignm ents constituted intentional

discrim ination against its fem ale em ployees. The Salaried Subclass m ade a

disparate-impact claim that Boeing’s com pany-wide practices for setting both

starting salaries and raises systematically disadvantaged its female employees and

a disparate-treatm ent claim that the company had failed to take action to correct

the discrim inatory im pact since learning of it in 1995. Not at issue are other

claim s brought by the two subclasses and the claim s of a putative subclass of

female salaried engineers.

II.   C LA SS C ER TIFIC A T IO N

      There have been several class-certification proceedings before the district

court in this case. The court’s initial certification decision, on April 25, 2003,

granted certification under Rule 23(b)(2) to both the Hourly and Salaried

Subclasses on their disparate-impact claims. Certification was denied on all

disparate-treatm ent claim s. On February 24, 2004, following m erits discovery,

the court granted Boeing’s m otion to decertify the disparate-im pact claim of the

Salaried Subclass, leaving the overtime disparate-impact claim of the Hourly

Subclass as the only claim certified for class-action treatm ent under Rule 23.

      Plaintiffs filed a Renewed M otion for Class Certification (First Renewed

M otion) on April 2, 2004, seeking recertification of the Salaried Subclass’s

disparate-im pact claim s. The court prom ptly denied the motion. Plaintiffs filed a

Second Renewed M otion for Class Certification (Second Renewed M otion) on

                                         -7-
August 27, 2004, seeking certification of the disparate-treatment claims of both

the Hourly and Salaried Subclasses and again asking for recertification of the

Salaried Subclass’s disparate-im pact claim . The district court denied the motion

on Septem ber 8, 2004.

      Plaintiffs then filed with this court an application to appeal under

Rule 23(f) the denial of their Second Renew ed M otion as it related to the claim s

of the Salaried Subclass. Although Plaintiffs sought certification of the disparate-

treatm ent claim of the Hourly Subclass in their Second Renewed M otion, they

abandoned that issue on appeal. Despite asserting in the application that the relief

sought was “leave to appeal the district court’s decision denying Plaintiffs’

Second Renewed M otion for Class Certification,” Pet. for Perm ission to Appeal at

11, the application refers only to the claim s of the Salaried Subclass and its

argum ents relate only to the certification determ inations m ade with respect to that

subclass. Therefore, we will address only the claim s of the Salaried Subclass.

      Boeing argues that Plaintiffs’ application was untim ely under Rule 23(f),

and that we therefore lack jurisdiction to consider it. W e provisionally granted

the application pending briefing and argum ent on our jurisdiction and the m erits

of the appeal. Upon further consideration we dism iss the application as untimely

and do not reach the m erits of the appeal.

      A.     Fed. R . C iv. P. 23(f)




                                         -8-
       Rule 23 was am ended in 1998 to add subsection (f), which perm its

interlocutory appeals of district court orders granting or denying class

certification. It states:

       A court of appeals m ay in its discretion perm it an appeal from an
       order of a district court granting or denying class action certification
       under this rule if application is made to it within ten days after entry
       of the order. An appeal does not stay proceedings in the district
       court unless the district judge or the court of appeals so orders.

Fed. R. Civ. P. 23(f).

       Interlocutory appeals have long been disfavored in the law, and properly so.

They disrupt and delay the proceedings below. See 19 James W m . M oore,

M oore’s Federal Practice § 201.10[1] (3d ed. 2006) (“The purposes of the final

judgm ent rule are to avoid piecem eal litigation, to prom ote judicial efficiency,

and to defer to the decisions of the trial court. Unfettered interlocutory appeals

would disrupt both the trial and appellate processes.”); 15A Charles A lan W right,

Arthur R. M iller & Edward H. Cooper, Federal Practice and Procedure § 3907, at

269 (2d ed. 1991) (“W hen courts attempt to explain the policies that underlie the

final judgm ent rule, . . . [they] speak of ‘efficiency,’ protecting the role of the

trial judge, and the need to avoid such evils as interference with the trial court,

deciding unnecessary issues, and deliberate delay or harassm ent.”). But

som etim es countervailing considerations predominate. The consideration that led

to adoption of subsection (f) is that a class-certification determ ination can force a

resolution of the case that is independent of the merits. W hen class-action status

                                           -9-
is denied, the plaintiffs m ay need to abandon the case, or settle for a pittance,

because the cost of continuing will far outweigh any potential recovery in the

individual actions remaining. And when class-action status is granted, the

defendant m ay be facing such enorm ous potential liability that a significant

settlem ent becom es the only prudent course. As the Advisory Com m ittee note

puts it:

       [S]everal concerns justify expansion of present opportunities to
       appeal. An order denying certification m ay confront the plaintiff
       with a situation in which the only sure path to appellate review is by
       proceeding to final judgm ent on the m erits of an individual claim
       that, standing alone, is far smaller than the costs of litigation. An
       order granting certification, on the other hand, m ay force a defendant
       to settle rather than incur the costs of defending a class action and
       run the risk of potentially ruinous liability. These concerns can be
       m et at low cost by establishing in the court of appeals a discretionary
       power to grant interlocutory review in cases that show appeal-worthy
       certification issues.

Fed. R. Civ. P. 23 advisory com m ittee’s note, 1998 Am endm ents, Subdivision (f).

       But this opportunity for an interlocutory appeal is tightly confined. First,

“[t]he court of appeals is given unfettered discretion whether to permit the appeal,

akin to the discretion exercised by the Supreme Court in acting on a petition for

certiorari.” Id. And second, there is a short time limit— 10 days— within which

the aggrieved party can ask the court of appeals to exercise its discretion. See id.

(“The 10-day period for seeking permission to appeal is designed to reduce the

risk that attempted appeals w ill disrupt continuing proceedings.”). Because this



                                          -10-
timeliness requirement is mandatory 1 , we m ust first determine w hether Plaintiffs

satisfied it.

       B.       T im eliness

       The district court denied Plaintiffs’ Second Renewed M otion by order

entered on September 8, 2004. Plaintiffs assert that their application filed on

September 22, 2004, was tim ely because it was filed within 10 days of the district

court’s disposition. See Fed. R. Civ. P. 6(a) (com putation of time); Beck v.

Boeing Co., 320 F.3d 1021, 1022-23 (9th Cir. 2003) (Fed. R. Civ. P. 6(a) governs

the tim eliness of applications under Rule 23(f)). The validity of that assertion

depends on whether the district court’s denial was “an order . . . granting or

denying class action certification.” Fed. R. Civ. P. 23(f). Boeing contends that

the district court’s order was sim ply a refusal to reconsider its prior rulings



       1
        W e are among several circuits that have treated the timeliness requirement
as jurisdictional. See, e.g., Delta Airlines v. Butler, 383 F.3d 1143, 1144 (10th
Cir. 2004) (per curiam ) (“Because the petition was not filed within the mandated
time period, we dism issed for lack of jurisdiction.”); M cNamara v. Felderhof, 410
F.3d 277, 280 (5th Cir. 2005) (“Unless som e exception applies, we lack appellate
jurisdiction to entertain the [untim ely] petition.”). The Supreme Court’s recent
decision in Eberhart v. United States, 126 S.Ct. 403, 406 (2005), however, casts
doubt on the notion that the timeliness of notices of appeal generally is
jurisdictional, see In re Special Grand Jury 89-2, 450 F.3d 1159, 1166 n.2 (10th
Cir. 2006), and could have similar implications for Rule 23(f), see Coco v.
Incorporated Village of Belle Terre, 448 F.3d 490, 491 (2d Cir. 2006) (per
curiam). Even if it is not jurisdictional, however, it is unquestionably
“mandatory” if properly raised by the opposing party, as was the case here.
Because we must dismiss the appeal in either event, we need not analyze
Eberhart’s impact on Rule 23(f).

                                          -11-
denying certification to the Salaried Subclass and not itself an order appealable

under Rule 23(f). W e agree with Boeing.

      In a sense, an order denying a m otion to reconsider a decision on class

certification is an “order . . . granting or denying class action certification.” But

that cannot be the sense in which the term is used in Rule 23(f), because that

construction of the term would underm ine the 10-day tim e lim it for filing an

application for review . One who failed to file an application in time could sim ply

file a m otion to reconsider; and when that is denied, the 10-day period would

restart. See Gary v. Sheahan, 188 F.3d 891, 893 (7th Cir. 1999) (“Accepting an

appeal from such a decision [leaving the class definition in place] would abandon

the tim e lim it for all practical purposes. That step would be both unauthorized

and imprudent.”); cf. M cNamara, 410 F.3d at 281 (“[T]o hold that— no m atter

how styled— a motion under Rule 23(c) [to alter or amend a class-certification

decision] is always distinct from a m otion to reconsider w ould allow a party to

subvert the ten-day tim e lim it prescribed in Rule 23(f).”).

      One might argue, as Plaintiffs do, that this reasoning does not apply when

the m otion for reconsideration raises new argum ents, based on new developm ents

in the case. But the need to avoid causing delay and disruption to the district

court proceedings cautions against an appellate court’s engaging in detailed

inspection and analysis of the record to determ ine how new an argum ent is and

whether the underlying evidence was reasonably available when certification was

                                         -12-
originally litigated. M oreover, there can be little doubt that review of an order

denying a motion for reconsideration would have to be lim ited to the new

elements in the motion— the original order regarding certification m ust be

presum ed correct, or there would be a clear end run around the 10-day lim it. Yet

given the multifactor analysis that courts m ust apply in deciding the propriety of

class certification, such a lim ited review would often require contorted thinking

that exceeds the capacities of even appellate courts. How can an appellate court

say that one particular new factor would require a different result regardless of

how the district court weighed the factors presented originally? In stating that the

new factor required a different result, the appellate court m ust engage in weighing

the factors weighed by the district court in its original ruling but cannot know

precisely how much weight the district court granted to each. In particular, what

if the district court clearly erred in giving dispositive weight to one factor? How

is the appellate court to ignore such error (in keeping with the presum ption that

the original decision was correct) even when it addresses a motion for

reconsideration that raises only a rather inconsequential new factor? To be sure,

we do review m otions to reconsider in certain circumstances, such as denials of

m otions under Fed. R. Civ. P. 60(b). But the predicate for that review— for

exam ple, fraud or newly discovered evidence— is largely collateral to the m erits

of the decision. W e are not inclined to adopt a construction of Rule 23(f) that

would regularly require m ental gym nastics just for the purpose of giving litigants

                                         -13-
a second bite at the interlocutory-appellate-review apple. W e note that the very

absence of a prom pt appeal by the party aggrieved by the decision on certification

suggests that the concerns justifying Rule 23(f) are, at the least, less significant in

the particular case. If the decision whether or not to certify the class w as truly

outcome determ inative, one would not expect the losing party to continue the

litigation for m onths before launching a new challenge to the ruling. Any value

in perm itting a belated interlocutory appeal is overridden by the desirability of the

district court’s proceeding expeditiously.

      W e recognize that Rule 23(c)(1)(C) perm its the district court to alter or

amend a certification decision. And parties m ay suggest such changes as the

factual record and legal theories develop. All we are saying is that there can be

no Rule 23(f) appeal from the denial of such a suggestion. An order that leaves

class-action status unchanged from what was determ ined by a prior order is not an

order “granting or denying class action certification.” Of course, when the

district court accepts a suggestion and the certification decision is changed, the

new order, to the extent it m odifies the prior order, is indeed such an order and an

interlocutory appeal under Rule 23(f) is perm itted. See G ary, 188 F.3d at 893

(“[I]f in response to a belated m otion for reconsideration the judge m aterially

alters the decision, then the party aggrieved by the alteration m ay appeal within

the normal time.”).




                                          -14-
      In addition, we note the special case of m otions to reconsider filed within

10 days of the district court’s certification decision. The Supreme Court has long

recognized that m otions to reconsider toll the tim e for appeal when they are filed

within the tim e for filing a notice of appeal. See United States v. Dieter, 429 U.S.

6, 8 & n.3 (1976) (“[T]he consistent practice in civil and crim inal cases alike has

been to treat tim ely petitions for rehearing as rendering the original judgm ent

nonfinal for purposes of appeal for as long as the petition is pending.”). This

recognition stems from the clear advantage of providing the district court an

opportunity to correct its own error, as long as doing so does not underm ine the

time limit for pursuing an appeal. W e assum e, without having to decide in this

case, that such m otions to reconsider w ould also toll the tim e lim it in Rule 23(f).

See, e.g., M cNam ara, 410 F.3d at 281 (recognizing the tolling effect of a timely

m otion to reconsider in the R ule 23(f) context).

      The district court first denied certification of the Salaried Subclass’s

disparate-treatm ent claim on April 25, 2003. Plaintiffs did not exercise their right

to file a Rule 23(f) petition within 10 days of that order. The district court’s

determ ination as to that claim has not changed in all the subsequent proceedings,

so there has not been any other order “granting or denying class action

certification” that would trigger another period for seeking interlocutory appeal.

As for class certification of the Salaried Subclass’s disparate-im pact claim , the

district court initially certified the class in its April 25, 2003, order, which Boeing

                                           -15-
did not appeal. On February 24, 2004, however, it granted Boeing’s m otion to

decertify. At that juncture Plaintiffs could have sought our review under Rule

23(f), but they did not do so. Despite two attem pts to have the district court

recertify that claim , in both Plaintiffs’ First Renewed M otion and their Second

Renewed M otion, the district court’s ruling on certification has not changed

again. Therefore, neither of the orders denying those motions was an order

granting or denying certification and neither triggered a new period for filing a

Rule 23(f) application. Plaintiffs’ Rule 23(f) application on September 22, 2004,

m ust be dism issed as an untim ely attempt to have us review the court’s orders of

April 25, 2003, and February 24, 2004. Any appeal of those certification

decisions m ust await final judgm ent. See G ary, 188 F.3d at 892.

III.   SU M M A R Y JU D G M E N T

       On February 24, 2004, the district court granted Boeing’s m otion for

sum m ary judgment on the disparate-impact claim of the Hourly Subclass. On

August 11, 2004, the court certified that ruling as a final judgm ent, see Fed. R.

Civ. P. 54(b), and Plaintiffs filed a tim ely appeal. Boeing filed a cross-appeal

seeking decertification of this subclass should we reverse the sum m ary-judgm ent

ruling. B ecause w e affirm the district court’s grant of summary judgment, we

need not address the cross-appeal.

       A.    Standard of R eview




                                         -16-
      Our standard of review on sum m ary judgm ent is de novo; we apply the

sam e legal standard to be used by the district court. Garrison v. Gambro, Inc.,

428 F.3d 933, 935 (10th Cir. 2005). Sum m ary judgm ent should be granted if “the

pleadings, depositions, answers to interrogatories, and admissions on file,

together with the affidavits, if any, show that there is no genuine issue as to any

m aterial fact and that the moving party is entitled to a judgm ent as a matter of

law.” Fed. R. Civ. P. 56(c). Neither “mere assertions and conjecture,” York v.

AT& T Co., 95 F.3d 948, 955 (10th Cir. 1996), nor “the existence of a scintilla of

evidence in support of the nonmovant’s position,” Lawmaster v. W ard, 125 F.3d

1341, 1347 (10th Cir. 1997), is sufficient to show a genuine issue of m aterial fact;

“an issue of m aterial fact is genuine only if the nonmovant presents facts such

that a reasonable jury could find in favor of the nonm ovant,” id.

      B.     Plaintiffs’ C laim

      Plaintiffs com plain that wom en have been the victim s of discrim ination in

the assignm ent of overtim e at Boeing’s W ichita facility, being offered and

receiving less than their proportionate share. They have raised both disparate-

treatment and disparate-im pact claims relating to overtim e. The sum m ary

judgm ent disposed of only their disparate-im pact claim .

      “An unlawful employm ent practice based on disparate im pact is established

. . . only if . . . a com plaining party dem onstrates that a respondent uses a

particular em ploym ent practice that causes a disparate im pact on the basis of . . .

                                          -17-
sex . . . .” 42 U.S.C. § 2000e-2(k)(1)(A)(i). The first step in raising a disparate-

im pact claim is to identify the specific employm ent practice allegedly causing the

discrim inatory im pact. See W ards Cove Packing Co. v. Atonio, 490 U.S. 642, 657

(1989) (“[A] plaintiff m ust demonstrate that it is the application of a specific or

particular employm ent practice that has created the disparate im pact under

attack.”); M aldonado v. City of Altus, 433 F.3d 1294, 1304 (10th Cir. 2006). The

specific practice identified by Plaintiffs is that “B oeing supplies no guidance to

m anagers on how to choose among eligible employees, and there are no

centralized rules for how to choose am ong equally eligible m ale and fem ale

employees.” R. Doc. 340 at 23 (Plaintiffs’ M em. in Opp’n to Boeing’s M ot. for

Sum m . J.); see also Aplt. Br. at 26. (In the sum m ary-judgm ent proceedings

below, and on appeal, Plaintiffs have also claim ed discrim inatory im pact from

Boeing’s failure to m onitor m anagers or hold them accountable for the gender

im pacts of their overtim e decisions. That allegation was not addressed by the

district court. Plaintiffs’ appellate briefs, however, contain no further elaboration

of this claim , so we will not specifically address it. See Gross v. Burggraf

Constr. Co., 53 F.3d 1531, 1546-47 (10th Cir. 1995) (“[I]t is insufficient merely

to state in one's brief that one is appealing an adverse ruling below without

advancing reasoned argum ent as to the grounds for appeal.” (internal brackets and

quotation m arks om itted)). In any event, our discussion of their claim that




                                          -18-
supervisors w ere given inadequate guidance in overtime assignm ents w ould likely

also be dispositive of this claim .)

      “U nder the disparate im pact theory, a plaintiff m ust first m ake out a prim a

facie case of discrim ination by showing that a specific identifiable employm ent

practice or policy caused a significant disparate im pact on a protected group.”

M urphy v. Derwinski, 990 F.2d 540, 544 (10th Cir. 1993) (internal quotation

m arks om itted). In other words, a plaintiff must “show that there is a legally

significant disparity between (a) the [gender] composition, caused by the

challenged em ploym ent practice, of the pool of those enjoying a job or job

benefit; and (b) the [gender] com position of the qualified applicant pool . . .

[, i.e.,] the pool from which potential qualified applicants m ight come.” Crum v.

Alabama (In re Em ployment Discrimination Litig. Against Ala., 198 F.3d 1305,

1312 & n.11 (11th Cir. 1999). The court compares the gender composition of

those who are subject to the challenged em ploym ent practice with the gender

com position of those enjoying the benefit for w hich the practice selects. In

assessing whether a plaintiff has established a prim a facie case, it is, of course,

irrelevant what happens to those who do not qualify for consideration. See Wards

Cove, 490 U.S. at 650-51 (“The proper comparison is between the racial

composition of the at-issue jobs and the racial composition of the qualified

population in the relevant labor m arket.” (emphasis added; internal quotation

m arks, brackets, and ellipsis om itted)).

                                             -19-
      Plaintiffs’ claim rests on the assertion that supervisors are exercising their

discretion (intentionally or subconsciously) to award m ales a disproportionate

share of available overtim e assignm ents. To establish a prim a facie case, it is not

enough for Plaintiffs to show sim ply that m ore overtim e assignm ents go to m en

than to wom en, or even that men get a higher percentage of those assignm ents

than their percentage in the work force. They must compare qualified m en to

qualified wom en. That is, they m ust show that am ong m en and wom en who are

eligible for overtim e assignm ents, a disproportionate share of overtim e

assignm ents go to m en.

      The qualifications for overtim e assignm ent are established in the collective

bargaining agreement (CBA) between Boeing and the International Association of

M achinists and A erospace W orkers AFL-CIO. The CBA provides:

      6.10(b) O vertim e Scheduling P rocedures for Extended W orkday
      or W orkw eek.
      (1) The norm al practice for the advance scheduling of overtim e
      within the shop and shift will be to:
             (a) First, ask the employee regularly assigned to either the
             m achine, job, crew, or position providing the em ployee is in
             attendance when the overtim e is being assigned . . . .
             (b) Then, ask other qualified employees in the same job
             classification who are in attendance when the overtim e is being
             assigned.
             (c) If sufficient volunteers are not obtained, the Com pany may
             designate any em ployee to satisfy remaining requirem ents.
      (2) M anagem ent m ay exclude an em ployee from overtim e, even if the
      em ployee is in attendance when the overtim e is being assigned, if:
             (a) The em ployee has been absent during the week . . . .




                                          -20-
             (b) An employee is asked to work overtim e (Saturday and/or
             Sunday) and is subsequently absent due to illness or
             bereavem ent leave on the workday preceding the overtim e day.
             (c) Two (2) consecutive weekends have been worked by
             the employee.
             (d) One hundred forty-four (144) overtim e hours have been
             worked in the budget quarter.
             (e) Eight (8) overtim e hours have been worked on the Saturday
             or the Sunday.
             (f) A n em ployee’s schedule perform ance or work quality is
             currently docum ented as being deficient.

Rep. Aplts. Supp. App. Vol. 1 at 10-11. (This provision is from the September 2,

1999, CBA. The 1995 CBA m ay be applicable to a portion of the class period,

which runs from April 2, 1999. Plaintiffs acknowledge, however, that the

overtim e provisions did not change m aterially during the class period.) Plaintiffs

do not dispute that the CBA applies to the challenged overtim e assignm ents.

Their claim is that the discretion exercised by managers in “choos[ing] among

employees who worked in the area where overtim e was required and wanted the

extra pay” has created a disparity betw een sim ilarly situated m en and wom en.

A plt. Br. at 26. Boeing for its part does not dispute that supervisors have som e

m easure of discretion within the term s of the CBA. It argues, however, that

Plaintiffs have failed to m ake a sufficient showing that this discretion has been

exercised in a manner adverse to wom en.

      On appeal Plaintiffs contend that their statistical evidence of disparate

impact suffices to preclude sum m ary judgm ent. (In district court Plaintiffs also

presented a variety of anecdotal evidence to support this claim . But because on

                                         -21-
appeal they do not rely on that evidence in challenging summary judgment, we

will consider only the statistical evidence.) They rely on a study by their expert,

Dr. Bernard Siskin. Dr. Siskin perform ed a regression analysis that compared the

overtime worked by m ale and fem ale em ployees w hom he defined as “sim ilarly

situated.” R. Doc. 346 (Decl. of Bernard P. Siskin, Ph.D. in O pp’n to Boeing’s

M ot. for Sum m . J. (hereinafter “Siskin Study”)) at 22. The Siskin Study

exam ined overtime assignm ents from April 2, 1999 (the beginning of the liability

period for this claim ) through June 20, 2002, using Boeing’s electronic daily

payroll records. For weekday overtime the Siskin Study defined sim ilarly

situated employees as those who “[w]orked that day and are in the same job,

grade, budget code and shift.” Id. at 23. Similarly situated em ployees w ith

respect to weekend overtim e w ere defined as those w ho “[w ]orked Friday and are

in the same job, grade, budget code and shift.” Id. For each cohort of sim ilarly

situated employees, the Siskin Study calculated three measures for m en and

wom en: (1) the likelihood of working any overtim e; (2) the average number of

overtime hours w orked; and (3) the average num ber of overtime hours paid

(overtim e is paid at either 1.5 or 2 tim es a normal hour). It then computed a

shortfall num ber for fem ales that described how m uch greater each m easure

would be were females represented in proportion to their percentage

representation in each cohort. “That is, if fem ales were 25 percent of the cohort,




                                        -22-
they should be 25 percent of those working overtim e and receive 25 percent of the

overtim e hours and pay.” Id. at 22.

      The Siskin Study concluded that “[h]ourly fem ale em ployees who are

sim ilarly situated to m ales with respect to job, grade, shift, departm ent, and

budget code are consistently and highly statistically significantly less likely to

work overtime, to w ork less overtime, and to receive less overtime pay. This

pattern is consistent across tim e.” Id. at 3. It observed that “[c]learly, som ething

in the overtim e process consistently results in m ales obtaining m ore overtim e and

working m ore overtim e than females.” Id. at 23.

      There is no dispute that “som ething” causes m en to work proportionately

m ore overtim e than wom en at Boeing. The district court said that the following

sum m ary was uncontroverted for purposes of sum m ary judgm ent:

       Between April 2, 1999, and Decem ber 31, 2001, disparities in
       overtim e adverse to w om en ranged between a low of 17.06 standard
       deviations and a high of 38.03 standard deviations. For the last
       period for which Dr. Siskin has analyzed data, ending June 20, 2002,
       the disparities w ere 10.23 standard deviations for w eekday overtim e
       and 7.95 standard deviations for weekend overtim e.

Rep. Aplts. App. Vol.1 at 280.

      Boeing concedes that these differences are statistically highly significant.

The Supreme Court has recognized that a disparity of m ore than two or three

standard deviations in a large sample makes “suspect” the contention that the

differential occurs random ly. See Hazelwood Sch. Dist. v. United States, 433



                                          -23-
U.S. 299, 308 n.14 (1977); Castaneda v. Partida, 430 U.S. 482, 496 n.17 (1977).

Several circuit courts have adopted a similar level of significance in Title VII

cases. See, e.g., Smith v. Xerox Corp., 196 F.3d 358, 366 (2d Cir. 1999); Brown

v. Philip M orris Inc., 250 F.3d 789, 809 (3d Cir. 2001); Lewis v. Bloomsburg

M ills, Inc., 773 F.2d 561, 568-69 (4th Cir. 1985) (five to eight standard

deviations); Adams v. Ameritech Servs., Inc., 231 F.3d 414, 424 (7th Cir. 2000).

But despite recognizing that the statistics show that m en have worked

proportionately m ore overtim e than wom en, Boeing claim s that the Siskin Study

nonetheless fails to establish a prim a facie case. It contends that the Siskin Study

does not show that the “som ething” causing m en to work m ore overtim e than

wom en is the manager discretion that Plaintiffs have identified as the challenged

em ploym ent practice. Boeing’s argum ent appears to be that the “som ething” is a

variable other than those that the Siskin Study included in the statistical

m odel— nam ely, job, grade, budget code, and shift. According to Boeing, other

variables affecting overtim e assignm ents— such as the CBA criteria and potential

differences in the rates at which men and wom en volunteer for overtim e— are not

controlled for in the Siskin Study and could be responsible for the observed

disparities. The district court agreed with Boeing that a statistical study could not

establish a claim without considering such variables and granted Boeing’s m otion

for sum m ary judgm ent on that basis. Before addressing Boeing’s argum ents, with




                                         -24-
which we agree in part, we review the legal framework for the use of statistical

evidence in Title VII cases.

      C.     Statistical E vidence - G eneral Principles

      Statistical evidence is an acceptable, and comm on, m eans of proving

disparate im pact. See, e.g., Sandoval v. City of Boulder, 388 F.3d 1312, 1326

(10th Cir. 2004); Bullington, 186 F.3d at 1312 (“As is typical in disparate im pact

cases, [plaintiff] relies on statistical evidence to establish her prim a facie case.”);

M ountain Side Mobile Estates P’ship v. Sec’y of HUD, 56 F.3d 1243, 1251 (10th

Cir. 1995) (“In Title VII em ploym ent discrim ination cases, plaintiffs m ay rely

solely on a statistical showing of disparate effect to establish a prim a facie case of

disparate im pact.”). The statistics m ust, however, relate to the proper population.

For example, when the claim is disparate im pact in hiring, the statistics should be

based on data with respect to persons qualified for the job. See W ards Cove, 490

U.S. at 650-51 (“It is such a com parison— between the racial composition of the

qualified persons in the labor m arket and the persons holding at-issue jobs— that

generally form s the proper basis for the initial inquiry in a disparate-im pact

case.”); see also Bullington, 186 F.3d at 1314 (“[Plaintiff’s] applicant pool was

appropriately limited to persons w ho sought out and were at least m inimally

qualified for the position . . . .”). The same requirement applies to other job

benefits. See Crum, 198 F.3d at 1309, 1312 (relating to alleged discrim ination in

“layoffs, recalls from layoffs, term inations, discipline, hiring, rehiring,

                                          -25-
evaluations, com pensation, transfers, job duty assignm ents, recruitment,

screening, selection procedures, denial of prom otions, demotions, rollbacks, sick

leave, subjective decision-m aking practices, and other term s and conditions of

em ploym ent” (internal quotation m arks om itted)). The essential requirem ent is

that the data concern those persons subject to the challenged em ploym ent

practice.

       After specifying the employm ent practice allegedly responsible for
       excluding m em bers of their protected class from a benefit, plaintiffs
       m ust identify the correct population for analysis. In the typical
       disparate im pact case the proper population for analysis is the
       applicant pool or the eligible labor pool. The com position of this
       population is com pared to the com position of the em ployer's
       workforce in a relevant m anner, depending on the nature of the
       benefit sought.

Smith, 196 F.3d at 368. W hen the selection process is only partially subjective, a

disparate-im pact plaintiff should control for the constraints placed upon the

decisionm aker’s discretion. See Anderson v. W estinghouse Savannah River Co.,

406 F.3d 248, 266-67 (4th Cir. 2005); cf. W atson v. Fort W orth Bank & Trust,

487 U.S. 977, 994 (1988) (O’Connor, J., plurality opinion) (“Especially in cases

where an em ployer com bines subjective criteria w ith the use of m ore rigid

standardized rules or tests, the plaintiff is in our view responsible for isolating

and identifying the specific em ploym ent practices that are allegedly responsible

for any observed statistical disparities.”).




                                          -26-
      To be sure, the population selected for statistical analysis need not

perfectly m atch the pool of qualified persons. Such perfection m ay be impossible

to obtain. W hen reliable data regarding that pool are unavailable, a different

population m ay be used if it adequately reflects the population of qualified

persons. See Ramona L. Paetzold & Steven L. W illborn, The Statistics of

Discrim ination § 5.04 (2002) (“In som e instances, where applicant data are not

available, reliable, or are believed to be biased, and where statistical inform ation

regarding the labor m arket is difficult to ascertain, the general population m ight

adequately reflect the population of qualified job applicants.”); see also M alave v.

Potter, 320 F.3d 321, 326-27 (2d Cir. 2003) (“[I]t was error [to reject] out of hand

[Plaintiff’s] statistical analysis sim ply because it failed to conform to the

preferred m ethodology described in W ards Cove, given the Suprem e Court’s

express endorsement in that decision of alternative methodologies if the preferred

statistics are ‘difficult’ or ‘im possible’ to obtain.”); cf. Trout v. Lehman, 702 F.2d

1094, 1102 (D.C. Cir. 1983) (in disparate-treatment case brought before the Civil

Rights A ct of 1991, “plaintiffs cannot legitim ately be faulted for gaps in their

statistical analysis when the inform ation necessary to close those gaps was

possessed only by defendants and was not furnished either to plaintiffs or to the

Court” (internal quotation m arks om itted)), vacated on other grounds by Lehman

v. Trout, 465 U.S. 1056 (1984), and abrogated on other grounds by Berger v. Iron

W orkers Reinforced Rodmen, Local 201, 170 F.3d 1111, 1124-25 (D.C. Cir.

                                          -27-
1999). For example, in Dothard v. Rawlinson, 433 U .S. 321 (1977), the Suprem e

Court determ ined that plaintiffs who were challenging Alabama’s height and

weight requirements for prison guards could use height and weight statistics based

on national data for com parison. “[R ]eliance on general population dem ographic

data was not m isplaced where there was no reason to suppose that physical height

and weight characteristics of Alabama men and wom en differ m arkedly from

those of the national population.” Id. at 330.

      Nevertheless, absent a close fit between the population used to m easure

disparate im pact and the population of those qualified for a benefit, the statistical

results cannot be persuasive. “[S]tatistics based on an applicant pool containing

individuals lacking m inim al qualifications for the job would be of little probative

value.” W atson, 487 U.S. at 997.

      Thus, a statistical analysis cannot establish a plaintiff’s prim a facie case

unless it is based on data restricted to qualified em ployees, or (1) reliable data

with respect to that group are unavailable and (2) the plaintiff establishes that the

statistical analysis uses a reliable proxy for qualification. This approach holds

plaintiffs to their statutory burden to “dem onstrate[] that a respondent uses a

particular em ploym ent practice that causes a disparate im pact on the basis of . . .




                                          -28-
sex,” 42 U.S.C. § 2000e-2(k)(1)(A )(i), without imposing an insurm ountable

burden when reliable data on a qualification are not available. 2

      D.     A pplication to this C ase

      The employm ent practice challenged by Plaintiffs is the exercise of

discretion by supervisors in assigning overtim e. As stated in Smith, “[T]he proper


      2
        The statute provides another avenue for plaintiffs when the particular
aspect of the process that is claimed to be objectionable cannot be isolated:

      [T]he complaining party shall demonstrate that each particular
      challenged employment practice causes a disparate impact, except
      that if the complaining party can demonstrate to the court that the
      elements of a respondent’s decisionmaking process are not capable of
      separation for analysis, the decisionmaking process may be analyzed
      as one employment practice.

42 U.S.C. § 2000e-2(k)(1)(B)(i). Plaintiffs argue in their reply brief to this court
that they “presented facts below that defendant’s collective bargaining agreements
imposed no meaningful objective standards on supervisors in assigning overtime”
and that “[s]uch a showing is sufficient to trigger subsection 2000-
e2(k)(1)(B)(i).” Rep. Aplts. Reply Br. at 10. But they provide no citation to the
record showing that they raised this issue in district court, and we cannot find in
the record anything indicating to that court that they were attempting to make the
required showing of analytical inseparability. W e will not address the potential
application of § 2000e-2(k)(1)(B)(i) to Plaintiffs’ claim, because our general rule
is not to address arguments that were not first presented to the district court, see
Cummings v. Norton, 393 F.3d 1186, 1190 (10th Cir. 2005) (the “general rule that
issues not raised below are waived on appeal” is particularly important on appeal
of summary judgment); Bancamerica Commercial Corp. v. M osher Steel of
Kansas, Inc., 100 F.3d 792, 798-99 (10th Cir. 1996) (“W here a litigant changes to
a new theory on appeal that falls under the same general category as an argument
presented at trial or presents a theory that was discussed in a vague and
ambiguous way the theory will not be considered on appeal.” (brackets and
internal quotation marks omitted)), and we particularly frown on the making of
new arguments in a party’s reply brief, see Stump v. Gates, 211 F.3d 527, 533
(10th Cir. 2000).

                                          -29-
population for analysis is the . . . eligible labor pool.” 196 F.3d at 368. The

Boeing hourly employees eligible for an overtim e assignm ent are those who

satisfy the CBA requirements for the assignm ent; that is, the challenged practice

operates only w ith respect to employees eligible under the CBA. The CBA

requires that overtime first be offered to “the em ployee regularly assigned to

either the machine, job, crew, or position” for which overtim e is to be scheduled,

and then to others within the sam e “shop or shift.” Rep. Aplts. Supp. App. Vol. 1

at 10. The Siskin Study, however, did not incorporate the CBA’s eligibility

requirements in its analysis. Instead, it controlled for “job,” “grade,” “budget

code,” and “shift.” R. Doc. 346 at 23. The implicit assum ption is that two hourly

workers with the same job, grade, budget code, and shift have equal opportunities

for overtim e assignm ents under the CBA, subject to the supervisor’s discretion.

There is certainly overlap between the Siskin Study variables and those used to

determ ine overtim e assignm ents. But the tw o sets of variables are not the sam e.

Am ong the qualifications included in the CBA, the Siskin Study controlled for

only “job” and “shift.” It did not account for whether wom en worked on the

“machine” or were in the “crew,” “position,” or “shop” to which the overtim e was

assigned. This failure can skew the results. If, for exam ple, overtim e

assignm ents were concentrated in a handful of shops and alm ost no wom en

worked in those shops, a discrepancy found in the Siskin Study between the

overtime worked by m en and by wom en would not at all represent a disparate

                                         -30-
impact created by the supervisor’s discretionary choice am ong eligible

employees. Rather, it could sim ply be a reflection of the gender distribution

among those eligible for overtim e. At the outset, therefore, it appears that the

Siskin Study cannot establish a prim a facie case based on a com parison “between

(a) the [gender] composition, caused by the challenged em ploym ent practice, of

the pool of those enjoying a . . . job benefit; and (b) the [gender] composition of

the qualified applicant pool,” Crum, 198 F.3d at 1312, because the study is not

lim ited to data regarding those qualified people subject to the challenged practice.

The study does not isolate the effect of supervisor discretion from the effect of

the CBA requirem ents. See Anderson, 406 F.3d at 260.

      Accordingly, we look to whether Plaintiffs have adequately established that

(1) reliable data on the omitted CBA criteria were unavailable and (2) they used a

reliable proxy. They have not. To begin with, Plaintiffs have not established that

the data necessary to establish the im pact on CBA-qualified workers were

unavailable. Plaintiffs acknowledge that variables such as crew, position, and

shop are relevant to qualification for overtim e under the CBA but claim that they

cannot be held responsible for including them in their statistical analysis because

“Boeing did not m aintain electronic data on any of the omitted variables.” Rep.

Aplts. Br. at 35. But data m ay be available in nonelectronic form . Electronic

data are undeniably m ore convenient, especially for use in statistical studies, but

inconvenience does not excuse failure to collect the data. Plaintiffs have

                                         -31-
presented no reason why the omitted inform ation could not have been procured

through other m ethods, such as depositions or interrogatories. It appears that they

were sim ply satisfied with Boeing’s indication that the data w ere unavailable in

their electronic payroll records.

      Furtherm ore, even were we convinced that the data are unavailable,

Plaintiffs have failed to dem onstrate that the variables in the Siskin Study’s

statistical analysis produce a reliable surrogate for qualifications for overtim e;

that is, that the results accurately reflect comparisons between individuals who

were equally eligible for overtim e assignm ents under the CBA. Plaintiffs m ake

the bald claim that the “grade” and “budget code” variables used by the Siskin

Study are equivalent to the omitted variables “crew,” “position,” and “shop.” See

Rep. Aplts. Reply Br. at 5 (“[I]n the absence of specific electronic data

m aintained by Boeing identifying employees’ ‘shops’ or ‘crews,’ [Dr. Siskin]

closely tracked this inform ation by using as a proxy budget codes and grade

levels that reflected their area and level of w ork.”). But they m ake no attem pt to

explain the basis of this claim . W e cannot agree that those relationships are as

self-evident as Plaintiffs apparently believe them to be. The record does not even

indicate what a “budget code” is. Plaintiffs’ “m ere assertion” will not suffice.

See York, 95 F.3d at 955. Accordingly, we agree with the district court that the

Siskin Study was insufficient to establish a prim a facie disparate-im pact case.




                                         -32-
      Plaintiffs rely on Bazemore v. Friday, 478 U.S. 385, 400 (1986), and

Bullington, 186 F.3d at 1314, to argue that failure to define perfectly the

population of qualified employees does not prevent the Siskin Study from

establishing their claim . Both decisions are distinguishable, however, because

the m issing variables considered by the two courts did not relate to m inimal,

objective qualifications. A jury could decide that the m issing variable in those

cases w as not likely to affect the exercise of discretion to a significant extent— a

rather different matter from ignoring a factor that disqualifies a candidate before

discretion comes into play.

      In Bazemore the United States and others brought a pattern-or-practice suit

against the North Carolina Agricultural Extension Service, alleging racial

discrim ination in salaries; the plaintiffs offered statistical evidence that controlled

for race, education, tenure, and job title. See 478 U.S. at 398. The court of

appeals had upheld the district court’s rejection of the statistical evidence, ruling

that “‘the regression analysis presented here must be considered unacceptable as

evidence of discrim ination,’” because it “‘om itted . . . variables which ought to be

reasonably viewed as determ inants of salary,’” id. at 399-400 (quoting Bazemore

v. Friday, 751 F.2d 662, 672 (4th Cir. 1984)), particularly geographic variations

in salary, Bazemore, 478 U.S. at 399. The Supreme Court disagreed. Introducing

its analysis it noted that “if the defendants have not succeeded in having a case

dism issed on the ground that plaintiffs have failed to establish a prim a facie case,

                                          -33-
and have responded to the plaintiffs’ proof by offering evidence of their own, the

factfinder then must decide whether the plaintiffs have dem onstrated a pattern or

practice of discrim ination by a preponderance of the evidence.” Id. at 398. It

then said, “[I]t is clear that a regression analysis that includes less than ‘all

m easurable variables’ m ay serve to prove a plaintiff’s case . . . . W hether, in fact,

such a regression analysis does carry the plaintiff’s ultim ate burden will depend

in a given case on the factual context of each case in light of all the evidence

presented by both the plaintiff and the defendant.” Id. at 400 (internal citation

om itted). The Court remanded for consideration of the particular characteristics

of the regression analysis to determ ine whether it was sufficiently probative. A s

we understand the opinion, the regression analysis was not used to establish the

prim a facie case, but to prove discrim ination once the presence of a prim a facie

case was established, or at least uncontested. The prim a face case required a

showing that qualified blacks were receiving lower salaries than qualified whites.

The regression analysis then exam ined whether other factors— such as education,

tenure, and job title— could account for this difference. Failure to take into

account all potential factors did not necessarily render the regression analysis

unprobative.

      M oreover, there was no question in Bazem ore, as there is here, regarding

whether the data concerned persons who were not qualified or eligible for the

benefit at issue— namely, a higher salary. The statistical study compared salaries

                                           -34-
of persons employed by the extension service. The issue was whether discretion

in setting salaries was exercised in a discrim inatory m anner. The statistical study

took into account som e factors that m ight influence the exercise of discretion and

om itted others; but there is no indication that it om itted any factor that was a

nondiscretionary determ inant of salary (such as a maxim um salary established for

a specific job title).

       Bullington considered a disparate-impact claim of gender discrim ination in

the hiring of airline flight officers. See 186 F.3d at 1312. The plaintiff offered

statistics indicating that the interview pass rate for wom en was only 60% of the

pass rate for m en. See id. The district court rejected the statistical study and

granted sum m ary judgm ent to the airline, because the pass rates were not adjusted

for hypothesized differences in aeronautical experience betw een m en and wom en.

Id. at 1312-13. W e reversed, concluding that the statistics were “sufficiently

reliable” because the study was properly lim ited to individuals who were

m inim ally qualified for the positions (otherwise they would not have been given

an interview in the first place). Id. at 1314. Again, the statistical study examined

only the exercise of discretion— this tim e in the interview process. A jury can

weigh whether om ission of a factor that could affect the exercise of discretion

renders an analysis unpersuasive. But no one could disagree that an objective

eligibility requirem ent is a necessary com ponent of the analysis.




                                          -35-
      Thus, the variables om itted from the regression analyses in both Bazemore

and Bullington related to characteristics that did not affect whether the population

studied was “m inimally qualified” for the benefit sought. The geographic

variations in salary at issue in Bazem ore had nothing to do with whether a

particular individual was m inim ally qualified to receive a higher salary. See 478

U.S. at 398. In Bullington the level of aeronautical experience was certainly a

perm issible consideration in the interview process, but it was only one of m any

factors considered in a subjective determ ination, not a mandatory criterion for

being hired. In contrast, the Siskin Study did not confine itself to the persons

eligible for an overtim e assignm ent. See Ortega, 943 F.2d at 1245 (statistics not

probative because they did not take into account qualifications for the jobs

available).

      Our conclusion is not undermined by the “m assive overtim e disparities”

that Plaintiffs allege are revealed by the Siskin Study’s analysis. Rep. Aplts. Br.

at 38. They contend that these disparities are so large that a substantial disparity

would certainly be present even if the statistical analysis were adjusted to account

for the CBA requirements. Plaintiffs argue:

      Boeing’s expert report affirm atively demonstrated that the gender of
      the employee regularly assigned to the machine or position for which
      overtim e w ork w as needed w as largely irrelevant to the overtim e
      disparities. Boeing’s expert determ ined that, for 78% of overtim e
      opportunities, m ore than one em ployee was eligible to work the
      overtim e. Thus, even if there had been reason to believe that more
      m en than wom en were the sole employees regularly assigned to the

                                         -36-
      m achine or position for which overtim e work was required, less than
      25% of the overtim e opportunities studied by Siskin would have been
      affected by his om ission of this variable. Viewed in the light m ost
      favorable to plaintiffs, this fact casts grave doubt on whether the
      om ission of this variable explains the massive overtim e disparities
      found by Siskin, precluding the district court from rejecting Siskin’s
      analysis on this ground.

Id. at 37-38 (record citation om itted). As we now proceed to explain, however,

this argum ent misapprehends the statistical evidence by confusing the magnitude

of the disparities w ith their level of statistical significance, as m easured in

standard deviations.

      There is no dispute that the Siskin Study’s regression analysis reflected a

difference in the amount of overtim e worked by men and wom en that was m any

standard deviations removed from equality. The Siskin Study computed

departures from equal treatm ent of m en and wom en whose statistical significance

ranged from 7.95 standard deviations (weekend overtim e during 2002) to 38.03

(weekday overtim e during 1999). That statistical significance, however, does not

necessarily m ean that the departure from equality was large. For example, the

Siskin Study calculated that wom en worked an average of 19% fewer hours of

weekday overtim e in 1999, 17% fewer in 2000 and 2001, and 11% fewer in 2002.

For weekend overtim e it calculated that wom en worked an average of 18% fewer

overtim e hours in 1999, 19% fewer in 2000, 18% fewer in 2001, and 10% fewer

in 2002. Although notable, these are not what m ost would call “massive

disparities”— it is nothing like men receiving proportionately even twice as m uch

                                           -37-
overtim e as wom en. Indeed, guidelines from the Equal Em ploym ent Opportunity

Com m ission draw a line (albeit not a rigid one) at a 20% disparity:

      A selection rate for any race, sex, or ethnic group which is less than
      four-fifths (4/5)(or eighty percent) of the rate for the group with the
      highest rate will generally be regarded by the Federal enforcement
      agencies as evidence of adverse impact, while a greater than four-
      fifths rate will generally not be regarded by Federal enforcement
      agencies as evidence of adverse im pact.

29 C.F.R. § 1607.4(D); accord 28 C.F.R. § 50.14(4)(D) (Departm ent of Justice

Guidelines); see Smith, 196 F.3d at 365 (treating “four-fifths” guideline as

persuasive); Thom as v. M etroflight, Inc., 814 F.2d 1506, 1511 n.4 (identifying the

EEOC guideline as “[o]ne possible index of substantial disparity”); cf.

M aldonado, 433 F.3d at 1305 (“EEOC guidelines, while not controlling upon the

courts by reason of their authority, do constitute a body of experience and

inform ed judgm ent to which courts and litigants m ay properly resort for

guidance.” (internal quotation m arks om itted)).

      W hat the large num ber of standard deviations m eans is that the departure

from equality, w hatever its magnitude, is highly unlikely to be random. Of

course, when there are m assive disparities, the difference m ay be m any standard

deviations. But when, as here, there is a great deal of data, even a relatively

sm all difference m ay be highly statistically significant (that is, unlikely to be

random). Consider an experim ent involving 1,000,000 flips of a coin. The

canonical result, of course, would be 500,000 heads and 500,000 tails.       Say, the



                                          -38-
results were 510,000 heads and 490,000 tails. Although the magnitude of the

difference is sm all, only about 4% m ore heads than tails, the odds of such a

difference occurring in the absence of a weighted coin are exceedingly sm all— the

departure from equality is 20 standard deviations. The difference strongly

indicates som e influence on the results other than the operation of pure chance.

      Likewise, under the Siskin Study’s analysis, it is very, very unlikely that

the difference in the assignm ent of overtim e to m en and w om en w ith the sam e

job, grade, budget code, and shift is a random event. As the Siskin Study

observed, “Clearly, som ething in the overtime process consistently results in

males obtaining more overtime and working more overtime than females.” R.

Doc. 346 at 23. The large number of standard deviations tells us nothing about

what that “som ething” is, however, other than that it is not based on differences

in job, grade, budget code, or shift.

      As a result, it could be very im portant, contrary to Plaintiffs’ brief, that

nearly a quarter of the overtim e opportunities were in work done by only one

person if, as im pliedly assum ed in the above-quoted passage from Plaintiffs’

brief, men disproportionately held those positions or the offers of overtim e w ere

concentrated in such positions held by m en. (In such situations there is very

little, if any, supervisor discretion in the assignm ent of overtim e, because the

CBA provides that the person who norm ally perform s the work should be offered

it first.) Similarly, it could be quite im portant if men are disproportionately

                                         -39-
em ployed in crew s in w hich overtime is available to everyone in the unit. Of

course, such gender disparities in these positions could indicate discrim ination in

hiring for those jobs, but that is not the claim m ade by Plaintiffs. See Price v.

City of Chicago, 251 F.3d 656, 661 (7th Cir. 2001) (plaintiff’s statistical showing

that eligibility test may produce disparate im pact could not establish prim a facie

case w hen the test’s use is not the em ploym ent practice com plained of).

      An illustration m ay m ake this proposition clearer. Boeing’s expert,

Dr. W ard, conducted a study on overtime assignments that controlled for the CBA

criteria by surveying individual managers about the actual offers m ade to eligible

employees. For each overtim e assignm ent, Dr. W ard’s study determ ined who was

eligible under the CBA and then m easured whether m en were disproportionately

selected for the overtim e. These data were collected for only a portion of the

W ichita facility and only for a two-m onth period in 2003, so the study is hardly

dispositive of whether discrim ination occurred. But the results are instructive.

      W hen only one employee norm ally perform ed the work and was eligible for

the overtim e assignm ent, wom en received 14% (76 of 535) of the overtim e offers,

precisely what would be expected (according to the report) given their

representation in the jobs from which those overtim e assignm ents were m ade.

W hen multiple workers were eligible under the CBA for the assignm ent, wom en

received 23% (430 of 1855) of the offers, very slightly more than would be

expected. Overall, w om en received 21% (506 of 2390) of the overtim e offers.

                                          -40-
From these data it appears likely that wom en were significantly underrepresented

in those jobs for w hich only one w orker w as eligible for particular overtim e

assignm ents, and even though those jobs accounted for only 22% (535 of 2390) of

the overtim e assignm ents studied, this underrepresentation decreased wom en’s

percentage of overtim e offers from 23% (when more than one em ployee was

eligible) to 21% (the overall rate). That is approxim ately a 9% reduction in the

offer rate to wom en (21 is 91% of 23). In other words, contrary to what one

would expect if the above-quoted argum ent of Plaintiffs were valid, wom en

received 9% fewer offers than one would expect if one looked only at positions

for which more than one worker was eligible.

      Dr. W ard’s study illustrates how disparities of the m agnitude of those

found in the Siskin Study could result solely from underrepresentation of wom en

in jobs for w hich only one em ployee is eligible for overtim e assignm ents.

Likew ise, even in situations in w hich several employees are eligible to w ork

overtim e, wom en could be underrepresented in the crews m ost likely to receive

calls for overtim e work. Yet, Plaintiffs have not shown how the Siskin Study

parameters would account for such underrepresentation.

      W e do not mean to m ake too m uch of Dr. W ard’s study. W e certainly are

not saying that it disproves Plaintiffs’ allegations of disparate im pact. But that

study clearly shows the flaws in the reasoning of Plaintiffs’ brief— that the large

num ber of standard deviations calculated in the Siskin Study m akes it

                                          -41-
unnecessary to determ ine whether the parameters used in that study are good

proxies for the CBA eligibility requirements. To repeat, the very large number of

standard deviations does not m ean that the gross difference in the amount of

overtim e worked by men and wom en is itself large; it just m eans that the

difference is very unlikely to be random. But since the CBA requirements not

included in the Siskin Study m odel are not random, and may well im pact m en and

wom en differently (as Dr. W ard’s study suggests), the results of the Siskin Study

are consistent with the CBA requirem ents being the cause of the disparity in

overtim e assignm ents— at least in the absence of evidence that the Siskin Study’s

parameters are reliable proxies for the CBA requirements. There being no such

evidence, the Siskin Study does not satisfy Plaintiffs’ burden to establish a prim a

facie case.

IV .   C L AIM S OF D E A N P L AINT IFFS

       Also on appeal are claim s by the Dean Plaintiffs. They ask us to review the

district court’s denial of reconsideration of their removal as class representatives

and denial of their m otion for recusal of Judge Brown. The district court included

these rulings in its certification of a final judgm ent under Fed. R. Civ. P. 54(b).

W e review the rulings on both m otions for an abuse of discretion. See Price v.

Philpot, 420 F.3d 1158, 1167 n.9 (10th Cir. 2005) (m otion to reconsider is

reviewed for abuse of discretion regardless of whether it is construed as raised

under Fed. R. Civ. P. 59 or 60); Fymbo v. State Farm Fire and Cas. Co., 213 F.3d

                                         -42-
1320, 1321 (10th Cir. 2000) (finding that individual is not adequate class

representative is subject to abuse-of-discretion review); Higganbotham v.

Oklahoma ex rel. Oklahoma Transp. Comm’n, 328 F.3d 638, 645 (10th Cir. 2003)

(denial of m otion to recuse is reviewed for abuse of discretion). Neither decision

by the district court was incorrect, let alone an abuse of discretion.

      The district court based its initial ruling removing the Dean Plaintiffs as

class representatives on their ongoing demand to be paid a “consultant’s fee” of

15% of any attorney fees obtained by class counsel. In its denial of their m otion

to reconsider, the court stated that the Dean Plaintiffs’ repeated public references

to privileged conversations with class counsel only strengthened its initial

conclusion that they put their own interests above those of the class. Given such

conduct, we agree with the district court that the Dean Plaintiffs w ould not “fairly

and adequately protect the interests of the class” as required by Rule 23(a)(4).

See Rutter & W ilbanks Corp. v. Shell Oil Co., 314 F.3d 1180, 1187-88 (10th Cir.

2002) (“Resolution of two questions determ ines legal adequacy: (1) do the named

plaintiffs and their counsel have any conflicts of interest with other class

m embers and (2) will the named plaintiffs and their counsel prosecute the action

vigorously on behalf of the class?” (internal quotation m arks om itted)).

      Sim ilarly, the district court did not err in denying the D ean Plaintiffs’

m otion for recusal. As the court thoroughly explained in its order, their

“unsubstantiated suggestions, speculations, [and] opinions,” are insufficient to

                                         -43-
establish even the appearance of any bias, prejudice, or m isconduct that would

warrant judicial recusal. Rep. Aplts. Supp. App. Vol.1 at 73 (Dist. Ct. Order of

1/7/2004); see Bryce v. Episcopal Church in the Diocese of Colo., 289 F.3d 648,

659-60 (10th Cir. 2002) (discussing the standards for recusal). “[A] judge . . . has

as strong a duty to sit when there is no legitim ate reason to recuse as he does to

recuse when the law and facts require.” Bryce, 289 F.3d at 659 (internal

quotation m arks om itted). The district judge correctly recognized his duty to

continue to sit in this case.

V.     C O N C L U SIO N

       For the reasons stated above, Plaintiffs’ petition for perm ission to appeal is

DISM ISSED. The district court’s sum mary judgm ent and its denial of Plaintiffs’

m otion to reconsider that decision (04-3334) are A FFIRM ED. The district court’s

disposition of the m otions by the Dean Plaintiffs (04-3350) is AFFIRM ED.

Boeing’s cross-appeal (04-3351) is DISM ISSED as m oot.




                                         -44-
