          United States Court of Appeals
                       For the First Circuit


Nos. 15-1466
     15-1533

          BERARDO A. QUILEZ-VELAR; MARTA BONELLI-CABAN;
      BERARDO A. QUILEZ-BONELLI; CARLOS A. QUILEZ-BONELLI,

               Plaintiffs, Appellants/Cross-Appellees,

                                 v.

                          OX BODIES, INC.,

                Defendant, Appellee/Cross-Appellant.


          APPEALS FROM THE UNITED STATES DISTRICT COURT
                 FOR THE DISTRICT OF PUERTO RICO

      [Hon. Silvia L. Carreño-Coll, U.S. Magistrate Judge]


                               Before

                      Lynch, Selya, and Lipez,
                           Circuit Judges.


     José Luis Ubarri, with whom David W. Román and Ubarri & Roman
Law Office were on brief, for appellants.
     John M. Roche, with whom Kevin S. Taylor, Arron Nesbitt,
Taylor Anderson, LLP, Francisco J. Colon-Pagan, Francisco E.
Colon-Ramirez, and Colón & Colón, P.S.C. were on brief, for
appellee.

                             May 9, 2016
              LYNCH, Circuit Judge.              This diversity case arose from

the   death    of    Maribel         Quilez-Bonelli       following       an   automobile

accident involving Maribel's Jeep Liberty and a truck in use by

Municipality of San Juan employees that had fitted onto its trash

body an underride guard designed by Ox Bodies, Inc. ("Ox Bodies").

Maribel's family members brought suit in federal court against Ox

Bodies, seeking damages for, inter alia, defective design of the

underride guard.           A jury found Ox Bodies strictly liable for

defective     design     and    awarded       the     plaintiffs    damages       totaling

$6,000,000.      By special verdict form, the jury assigned 20% of

responsibility       for       the    damages        to   Ox   Bodies,     80%    to    the

Municipality of San Juan, which was not a party in the suit, and

0% to Maribel.       The presiding magistrate judge ruled that judgment

should   enter      on   the    strict       liability     claim    in    favor    of   the

plaintiffs and that under Puerto Rico law, Ox Bodies should be

held responsible only for 20% of the damages award, which equaled

$1,200,000.      This appeal and cross-appeal followed.

              Ox Bodies appeals the verdict, contending that the court

should not have allowed the plaintiffs' expert to testify on an

alternative      underride           guard    design,      and     that    absent       such

testimony, no reasonable jury could have found for the plaintiffs.

The plaintiffs appeal the order limiting their recovery, arguing

that under Puerto Rico law Ox Bodies should be held "jointly and

severally liable to the plaintiff[s] for the totality of the


                                             - 2 -
damages" -- the entire $6,000,000 award -- such that "the risk of

loss of having to pay the entire judgment without obtaining

contribution is borne by the defendant joint tortfeasor, not by

the plaintiffs."

            We affirm the court's decision to admit the plaintiffs'

expert's testimony and so reject Ox Bodies' appeal.          On the

plaintiffs' appeal, in the absence of clear Puerto Rico law, we

certify to the Puerto Rico Supreme Court the question of the extent

of Ox Bodies' liability for the damages award.

                                  I.

            On October 1, 2010, Maribel Quilez-Bonelli, a then 28-

year-old married woman and mother, was driving on a highway

overpass near the city of San Juan in a 2004 Jeep Liberty with her

toddler son when her Jeep collided with a stopped or slowly moving

truck in use by Municipality of San Juan employees.       The truck

bore an underride guard near its rear that had been designed by Ox

Bodies.    The front of Maribel's Jeep hit the truck from behind and

underrode the truck's trash body such that the truck penetrated

the Jeep's passenger compartment and struck Maribel, lacerating

her head and face. Maribel died from resulting injuries on October

6, 2010.

            Maribel's family members, Berardo A. Quilez-Velar, Marta

Bonelli-Caban, Berardo A. Quilez-Bonelli, and Carlos A. Quilez-




                                - 3 -
Bonelli1 (collectively "Quilez"), brought suit in a Puerto Rico

court and in federal court.2          In a Puerto Rico trial court, Quilez

filed an amended complaint on November 1, 2011, alleging negligence

and seeking damages from, inter alia, the Commonwealth of Puerto

Rico,       the   Puerto   Rico   Highway   and   Transportation    Authority,

Integrand Assurance Company ("Integrand"), and the Municipality of

San Juan.         The Municipality of San Juan and Integrand brought a

third-party complaint for indemnification or contribution against,

inter alia, Ox Bodies and its parent company, Truck Bodies &

Equipment International, Inc.           On May 16, 2014, the Municipality

of San Juan, through its insurer, deposited with the Puerto Rico

court       its    maximum   policy    limit,     $500,000,   for    potential

distribution if found liable.          The Puerto Rico court ordered that

the funds be distributed to the plaintiffs and dismissed the

Municipality of San Juan from suit.             Quilez expressly represented

to this court that "[n]o settlement agreement was ever executed

and [Quilez] granted no release [to] or assumed any liability"

from the Municipality of San Juan or its insurer.                   Ox Bodies




        1 For simplicity, we refer to Maribel Quilez-Bonelli as
"Maribel" and the plaintiffs as "Quilez" going forward.
        2 Maribel's surviving husband, Francisco Felix-Navas, and
her surviving son, Francisco Andres Felix-Quilez, together also
filed suit in a Puerto Rico court seeking damages resulting from
Maribel's accident. The two Puerto Rico suits were consolidated.


                                      - 4 -
conceded this point at oral argument, no document in the record

establishes otherwise, and so we accept Quilez's representation.

             On March 20, 2013, Quilez filed an amended complaint in

its diversity action in federal district court against Ox Bodies,

its parent company, and other defendants, for defective design and

negligence under Puerto Rico law. Ox Bodies and its parent company

brought      a     third-party       claim      for      contribution      and/or

indemnification against, inter alia, the Municipality of San Juan.

On May 16, 2014, the Municipality of San Juan notified the federal

court that it had deposited $500,000 that day with the Puerto Rico

court.    On September 4, 2014, the federal court dismissed the

Municipality of San Juan from the suit, without objection from Ox

Bodies.   Quilez-Velar v. Ox Bodies, Inc., No. CIV. 12-1780, 2014

WL 4385418, at *2, *3 (D.P.R. Sept. 4, 2014), reconsideration

denied, No. CIV. 12-1780, 2014 WL 4656649 (D.P.R. Sept. 17, 2014).

At the time of this appeal, the only remaining defendant is Ox

Bodies.

             On January 26, 2015, Ox Bodies filed a pre-trial motion

in limine to exclude the testimony of Quilez's expert, Perry

Ponder,   arguing     that    "Mr.   Ponder's    report     is    devoid   of   any

scientific       analysis    or   calculations    that    would    support"     his

conclusion that his proposed alternative underride guard design

"would have been [a] safer design in the instant accident," and

that his opinions should be excluded under Daubert v. Merrell Dow


                                      - 5 -
Pharmaceuticals, Inc., 509 U.S. 579 (1993).3   Ox Bodies supported

its motion with excerpts from Ponder's deposition and expert

report, but it did not request that Ponder testify at a Daubert

hearing.4   Quilez opposed the motion.

            After reviewing both parties' submissions and relevant

discovery materials, the magistrate judge, presiding pursuant to

28 U.S.C. § 636, denied the motion to exclude Ponder's testimony.

Quilez-Velar v. Ox Bodies, Inc., No. CIV. 12-1780, 2015 WL 418151,

at *7 (D.P.R. Feb. 1, 2015).   The magistrate judge acknowledged Ox

Bodies' argument that Ponder "did not perform specific tests or

calculations in the course of his analysis," but found, first,

that Ox Bodies failed to "show that these specific tests must have

been carried out to provide a foundation for Ponder's opinions,"



     3    Ox Bodies described a range of foregone calculations,
including, inter alia, that Ponder "did not calculate the peak
force of the collision, the coefficient of restitution, or the
average or maximum forces of the impact"; "he did not conduct any
analysis to determine the energy absorption that the proposed
design change could sustain"; the reports he "relied upon evaluated
impacts and forces that were different from those involved in this
case"; "he did not perform any finite element analysis"; and he
did not calculate the "loads created in a collision between a truck
and a passenger vehicle."
     4    A trial court may order a Daubert hearing to screen the
proffer of scientific testimony to determine whether it crosses
the Daubert threshold. See, e.g., Samaan v. St. Joseph Hosp., 670
F.3d 21, 31 (1st Cir. 2012). "[T]he scope of a Daubert hearing is
not limited to an appraisal of an expert's credentials and
techniques but also entails an examination of his conclusions to
determine whether they flow rationally from the methodology
employed." Id. at 32.


                               - 6 -
and second, that upon "review[ing] Ponder's report, . . . its

conclusions are well-explained, and its use of crash-test data

appears appropriate."     Id.

           At trial, when Quilez moved to qualify Ponder as an

expert,   Ox   Bodies   requested    voir    dire,   which   was   initially

conducted in front of the jury and during which Ponder acknowledged

that he did not crash-test his proposed alternative design and

that none of his "rear underride guard designs" had ever been

adopted by tilt or dump bed manufacturers.             Ox Bodies conceded

that Ponder was qualified as an accident reconstructionist but

renewed its objection to Ponder's testifying about an alternative

design for an underride guard.              The court permitted further

questioning by both parties outside the presence of the jury,

spanning more than nine pages of transcript, before ultimately

ruling that Ponder was qualified to testify about an alternative

underride guard design.

           Following a 12-day trial, the jury returned a verdict

finding Ox Bodies strictly liable to Quilez for defective design.

In the magistrate judge's March 3, 2015, memorandum and order,

damages were apportioned as described earlier.         Quilez-Velar v. Ox

Bodies, Inc., No. CIV. 12-1780, 2015 WL 898255, at *1–3 (D.P.R.

Mar. 3, 2015).




                                    - 7 -
                                    II.

            Ox Bodies appeals the admission of Ponder's testimony

regarding   a   feasible   safer   alternative   design,   arguing   that

without Ponder's testimony no reasonable jury could have found it

liable.     "Under Puerto Rican tort law governing design defect

claims, if the plaintiff proves that 'the product's design is the

proximate cause of the damage,' the burden shifts to the defendant

to prove that 'the benefits of the design at issue outweigh the

risk of danger inherent in such a design.'"           Quintana-Ruiz v.

Hyundai Motor Corp., 303 F.3d 62, 69 (1st Cir. 2002) (quoting

Aponte Rivera v. Sears Roebuck de P.R., Inc., 144 P.R. Dec. 830,

840 n.9 (1998), 1998 P.R.-Eng. 324486 n.9, 1998 WL 198857 n.9).

Here, the court instructed the jury that if it found that the

plaintiffs met their burden, then "[i]n deciding whether the

benefits outweigh the risks," it should consider a number of

factors, including "[t]he feasibility of an alternative safer

design at the time of manufacture."        Neither party contests this

instruction.5

            Ponder's expert report pointed to two key deficiencies

in Ox Bodies' guard design: first, "[a]pproximately the outside 16


     5    As we said in Quintana-Ruiz, "[t]here are at least three
views of how the existence, or non-existence, of a mechanically
feasible alternative design fits into the risk-utility balancing
test," 303 F.3d at 71, and "[i]t is not clear what view the Puerto
Rico courts would follow," id. at 72; see id. at 71–72 (describing
the three views).


                                   - 8 -
inches on each side of the rear of the [Ox Bodies] truck is left

without any underride guarding at all," and second, "the guard is

not sufficiently braced against impacts" because "[t]he outside

span of the horizontal member is a beam supported at an interior

location, but unsupported at the end," such that part of the guard

"would begin to fail at a load of approximately 7,000 lbs."            He

further opined that "[t]he frontal collision safety features in

[Maribel's] Jeep Liberty were rendered ineffective because the

. . . truck lacked a substantially constructed underride guard."

            Ponder's report went on to conclude that "[t]here exist

feasible safer alternative rear impact guard designs for" the truck

involved here.    He noted a number of published studies that "offer

completed truck underride guard designs."       He outlined a design

suited for the instant truck, "consist[ing] of a horizontal member

positioned at the or very close to the rear extremity of the

vehicle, long enough to protect the entire width of the truck,"

and "[d]iagonal bracing . . . placed at the truck bed's interior

longitudinal members and side longitudinal members at a 45 degree

angle along with a vertical support to complete the truss at the

side extremities."

            Our review of the magistrate judge's decision to admit

Ponder's    testimony   on   alternative   design   is   for   abuse   of

discretion.      Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152

(1999).    "Absent a material error of law, we will not second-guess


                                 - 9 -
such a discretionary determination unless it appears that the trial

court 'committed a meaningful error in judgment.'"         United States

v. Jordan, 813 F.3d 442, 445 (1st Cir. 2016) (quoting Ruiz-Troche

v. Pepsi Cola of P.R. Bottling Co., 161 F.3d 77, 83 (1st Cir.

1998)).    We find that under Federal Rule of Evidence 702, the

magistrate judge's decision to admit Ponder's testimony was within

her discretion.

           Under Federal Rule of Evidence 702:

           A witness who is qualified as an expert by
           knowledge, skill, experience, training, or
           education may testify in the form of an
           opinion or otherwise if:

           (a) the expert's scientific, technical, or
           other specialized knowledge will help the
           trier of fact to understand the evidence or to
           determine a fact in issue;
           (b) the testimony is based on sufficient facts
           or data;
           (c) the testimony is the product of reliable
           principles and methods; and
           (d) the expert has reliably applied the
           principles and methods to the facts of the
           case.

Fed. R. Evid. 702.    The magistrate judge here must "serve[] as the

gatekeeper for expert testimony by 'ensuring that [it] . . . both

rests on a reliable foundation and is relevant to the task at

hand.'"6    Milward   v.   Rust-Oleum   Corp.,   No.   13-2132,   2016   WL


     6    Although Ox Bodies' opening brief contends that whether
a trial court has acted as a gatekeeper is subject to de novo
review, see Smith v. Jenkins, 732 F.3d 51, 64 (1st Cir. 2013), Ox
Bodies has not argued that the magistrate judge failed to perform
that role.   And so any argument on that issue is waived.     See


                                 - 10 -
1622620,   at    *3    (1st   Cir.   Apr.   25,    2016)   (second       and   third

alteration in original) (quoting Daubert, 509 U.S. at 597).

           There is no dispute that testimony regarding alternative

design was necessary to determine a fact at issue.                The magistrate

judge acted within her discretion in determining that Ponder's

"scientific, technical, or other specialized knowledge" would help

the jury determine that issue.           Fed. R. Evid. 702(a).           Ponder, a

licensed   professional       engineer      with    a   degree    in     mechanical

engineering, has designed and tested at least four underride

guards, reviewed crash tests and underride crashes, and lectured

or   published    on    the    subjects     of     underride     guard     history,

regulations, and side underride guard protections.                     He is also

certified by the Accreditation Commission for Traffic Accident

Reconstruction as an accident reconstructionist and has performed

more than 400 accident reconstructions, including about twenty in

underride cases.       On appeal, Ox Bodies has not raised a developed




United States v. Zannino, 895 F.2d 1, 17 (1st Cir. 1990). Even if
properly raised, such an argument would be difficult in these
circumstances, as Ox Bodies neither requested a Daubert hearing
nor mentioned Daubert in its objection to Ponder's qualifications
during the voir dire at trial, and the magistrate judge entertained
Ox Bodies' arguments in ruling on its motion in limine and
permitted additional questioning at trial before ruling on
Ponder's qualifications. See Jenkins, 732 F.3d at 64 ("If we are
satisfied that the court did not altogether abdicate its role under
Daubert, we review for abuse of discretion its decision to admit
or exclude expert testimony.").


                                     - 11 -
objection to the relevance of these experiences to the issue at

hand.

               Rather, the central question before us concerns whether

the magistrate judge abused her discretion in concluding that

Ponder's testimony on alternative design was sufficiently reliable

to survive the admissibility threshold.7                 Ox Bodies asserts that

Ponder's testimony should have been excluded under Daubert because

the expert must have actually tested the alternative design, either

physically or using computer modeling, and Ponder did not do so.

Ox   Bodies'        argument   rests     on   a   profound   misunderstanding    of

Daubert, which eschews such per se approaches.                     See Kumho Tire

Co., 526 U.S. at 150 (holding that the inquiry "depends upon the

particular          circumstances   of    the     particular   case    at   issue");

Milward v. Acuity Specialty Prods. Grp., Inc., 639 F.3d 11, 16–20

(1st        Cir.    2011)   (conducting       a    fact-specific      "reliability"

inquiry).          "Testing is certainly one of the most common and useful

reliability guideposts for a district court when contemplating

proposed Rule 702 evidence."             Lapsley v. Xtek, Inc., 689 F.3d 802,

815 (7th Cir. 2012).           However, this circuit has never adopted a



        7 Under Daubert, courts may consider a number of factors
in assessing reliability: whether a theory or technique can be and
has been tested; whether it has been put through peer review and
has been published; whether it has a high error rate; and whether
it has been generally accepted within the relevant scientific or
technical community.   See Kumho Tire Co., 526 U.S. at 149–150;
Ruiz-Troche, 161 F.3d at 80–81.


                                         - 12 -
rule that an expert himself must have tested an alternative design,

much less by building one.   We decline to adopt either requirement

as a bright-line rule or as applied to this case.   See Kumho Tire

Co., 526 U.S. at 150 ("[T]he factors [Daubert] mentions do not

constitute a 'definitive checklist or test.'" (quoting Daubert,

509 U.S. at 593)); Johnson v. Manitowoc Boom Trucks, Inc., 484

F.3d 426, 431–33 (6th Cir. 2007) (declining to hold that testing

is a requirement or the sole, dispositive factor under Daubert);

Wagner v. Hesston Corp., 450 F.3d 756, 760 n.8 (8th Cir. 2006)

(noting that lack of testing is a "non-dispositive factor");

Watkins v. Telsmith, Inc., 121 F.3d 984, 990 (5th Cir. 1997)

("Testing is not an 'absolute prerequisite' to the admission of

expert testimony on alternative designs, but Rule 702 demands that

experts 'adhere to the same standards of intellectual rigor that

are demanded in their professional work.'" (quoting Cummins v.

Lyle Indus., 93 F.3d 362, 369 (7th Cir. 1996))); Cummins, 93 F.3d

at 369 ("We do not mean to suggest, of course, that hands-on

testing is an absolute prerequisite to the admission of expert

testimony.").8


     8    Neither of the reported appellate cases Ox Bodies cites
hold that testing is a dispositive requirement under Daubert
either. See Zaremba v. Gen. Motors Corp., 360 F.3d 355 (2d Cir.
2004); Oddi v. Ford Motor Co., 234 F.3d 136 (3d Cir. 2000).
Moreover, unlike here, those cases involved review of exclusion of
expert testimony. See Zaremba, 360 F.3d at 357–58; Oddi, 234 F.3d
at 156, 158. Ox Bodies also cites an unpublished opinion of a
divided Tenth Circuit panel that is irrelevant. See Hoffman v.


                               - 13 -
           In any event, the record permitted a factfinder to

conclude that Ponder did do some testing, and here, the record

supports the magistrate judge's determination that there were

alternate methods of testing from which the jury could evaluate

reliability.    See    Johnson,   484     F.3d   at   431.     First,   Ponder

testified that he looked at "crash test information" from several

sources,   including   a   1980   study    available    from   the   National

Technical Information System, "a number of patents," "crash test

data from 1971 from Aeronautical Research Associates," and other

crash tests done under contract with the National Highway Traffic

Safety Administration ("NHTSA").          Ox Bodies argues that Ponder's

conclusion regarding the guard in the instant case does not "fit"

with or follow from the studies.           In its motion in limine, Ox

Bodies argued that those studies "evaluated impacts and forces

that were different from those involved in this case."            But Ponder

testified in voir dire that at least some of the "information is

transferrable . . . [to] underride guards for any type of vehicle."

He explained in response to a question about crash-test data asked

during his deposition, for example, that "a 90-degree frontal test

is what NHTSA uses as confirmation for crash worthiness and



Ford Motor Co., 493 F. App'x 962, 975–76 (10th Cir. 2012) (finding
expert testimony unreliable where expert did not compare his
laboratory test results to either the accelerations on the buckle
in the instant accident or to published rollover crash tests, and
inconsistently claimed there was a lack of rollover crash data).


                                  - 14 -
passenger safety in crash types -- all crash types."        Upon review

of the arguments and documents in the record properly submitted to

us,9 we cannot say that it was an abuse of discretion for the

magistrate judge to conclude, as she did at trial, that "[Ponder]

had enough data that did not require him to conduct further testing

for research to base his opinions on."

           Second, Ponder testified that he tested his design using

"stress   calculation[s]."    Cf.   Lapsley,   689   F.3d   at   815   ("A

mathematical or computer model is a perfectly acceptable form of

test."). His reliance in part on a Society of Automotive Engineers

("SAE") article, in order to determine the energy involved as well

as "compar[e] the damage to [the SAE article's] damage matrix

index," was appropriate.10   Ponder also testified that he performed

"photogrammetry analysis" using calculations performed by hand to

test how his design would react upon impact.




     9    We limit our review to those documents in the record.
We will not consider supposed excerpts from Ponder's notes that
both Ox Bodies and Quilez attempt to submit to this court, as
neither party indicates their location in the record before the
magistrate judge, and we have not been able to pinpoint any of
these references.
     10   On appeal, Ox Bodies argues that because Ponder failed
to identify any industry manufacturer or government agency that
has adopted his design or a "similar" one, his design lacks "peer
review." Ox Bodies did not raise this exact argument in its motion
in limine or at trial, and so it is waived. See Sierra Club v.
Wagner, 555 F.3d 21, 26 (1st Cir. 2009).


                               - 15 -
            Ox    Bodies    contends      that     Ponder     failed   to   perform

calculations its expert said were necessary in testing his design.

However, as the magistrate judge correctly stated in ruling on Ox

Bodies' motion in limine, "Defendants do not show that these

specific tests must have been carried out to provide a foundation

for   Ponder's    opinions."           Moreover,    Ponder's     report     and   his

responses    when   questioned         during    his     deposition    demonstrate

support for his findings.               We emphasize that in most cases,

"[v]igorous cross-examination, presentation of contrary evidence,

and careful instruction on the burden of proof are the traditional

and appropriate means of attacking shaky but admissible evidence."

Daubert,    509   U.S.     at   596.     And     here,   Ox   Bodies   "had   ample

opportunity to cross examine" Ponder "and to use its own expert

witness -- which it did."              Diefenbach v. Sheridan Transp., 229

F.3d 27, 31 (1st Cir. 2000).

            Finally, on appeal Ox Bodies argues that Ponder did not

show that his alternative design would have "withstood the force

of the crash" and would have prevented intrusion into the passenger

compartment, or that the alternative design guard would have caused

"the Jeep to rotate away from the truck on impact, rather than

continuing further into the trash body."                 Ox Bodies did not raise

these objections in its motion in limine or in its objections at

trial. Arguably, the contention is waived. Sierra Club v. Wagner,

555 F.3d 21, 26 (1st Cir. 2009).            But even assuming that the more


                                        - 16 -
general argument -- that Ponder has not shown that his alternative

design would have prevented Maribel's injuries -- was properly

raised, that argument goes to the credibility of his testimony

that the design was "safer."              As these arguments were appropriate

to make to the jury when it weighed the evidence, they do not lead

us to conclude that the testimony's admission was in error.

                In short, admitting Ponder's testimony on alternative

design was not a "meaningful error in judgment," Ruiz-Troche, 161

F.3d at 83 (quoting Anderson v. Cryovac, Inc., 862 F.2d 910, 923

(1st Cir. 1988)), and we affirm the magistrate judge's decision to

admit his testimony.

                                          III.

                The   sole   issue   in    Quilez's   appeal   is   whether   the

magistrate judge erred by not holding Ox Bodies jointly and

severally liable11 for the entire $6,000,000 damages award.                   That

decision was based on a particular reading of the Puerto Rico

Supreme Court's decisions in Cortijo Walker v. P.R. Water Res.

Auth., 91 P.R. 557 (1964); Widow of Andino v. P.R. Water Res.

Auth., 93 P.R. 168 (1966); and Rosario Crespo v. P.R. Water Res.

Auth., 94 P.R. 799 (1967).           See Quilez-Velar, 2015 WL 898255, at

*2-3.        On our reading, those precedents do not clearly answer the



        11Joint and several liability sometimes goes by the name
"solidary" liability in Puerto Rico. Ramos v. Caparra Dairy, Inc.,
16 P.R. Offic. Trans. 78, 81 (1985).


                                      - 17 -
question at hand, and the question raises important public policy

concerns.    Because the issue is determinative of Quilez's appeal,

we find "the prudent course is to certify the question to that

court better suited to address the issue."12              Pagán-Colón v.

Walgreens of San Patricio, Inc., 697 F.3d 1, 18 (1st Cir. 2012).

We explain, without in any sense meaning to influence the outcome.

             The underlying assumption of the magistrate judge's

reasoning is that Ox Bodies had no right of contribution against

the Municipality of San Juan and that it necessarily followed that

Quilez could not recover the sum of $6,000,000 against Ox Bodies

on a joint and several liability theory. There are many questions,

as discussed below, about whether contribution is or is not

available,    and   whether   the   reasoning   tying   the   existence   of

contribution to the existence of joint and several liability is

valid under Puerto Rico law.        Quilez posits that even if Ox Bodies

does not have a right of contribution, Ox Bodies is nonetheless

responsible to Quilez as a jointly and severally liable defendant.

That is, the municipal cap does not excuse Ox Bodies from paying

the sum of $6,000,000; and so, it cannot have the effect of

shifting the risk of non-payment of the full sum to Quilez.




     12   At oral argument, the parties agreed that this court
could certify the issue, and we subsequently afforded them an
opportunity to propose language for the certification question.


                                    - 18 -
            The magistrate judge's March 3, 2015, order read the

Puerto Rico Supreme Court's decision in Cortijo Walker, which

disallowed a third-party suit by a defendant against a plaintiff's

employer covered by Puerto Rico's workmen's compensation statute,

91   P.R.   at   559,   566,   to   preclude     Ox   Bodies   from   seeking

contribution from the Municipality of San Juan.                Quilez-Velar,

2015 WL 898255, at *2. Then, the magistrate judge held that, under

Widow of Andino and Rosario Crespo, where "a defendant's general

right to contribution is lost due to a joint-tortfeasor's statutory

immunity," 2015 WL 898255, at *2, in a tort action a "defendant

should be held liable for the damage only in proportion to its

fault," id. at *3 (quoting Widow of Andino, 93 P.R. at 180); see

Rosario-Crespo, 94 P.R. at 813.13            Ox Bodies urges us to affirm

based on this reasoning.



      13  In a previous order, the magistrate judge also held that
Puerto Rico would likely follow Restatement (Third) of Torts:
Products Liability § 16 (Am. Law Inst. 1998), such that when an
injury is indivisible, if a plaintiff shows that a defectively
designed product "is a substantial factor in increasing the
plaintiff's harm beyond that which would have resulted from other
causes, the product seller is subject to liability for . . .
plaintiff's harm attributable to the defect and other causes" and
is "liable with other parties who bear legal responsibility for
causing the harm, determined by applicable rules of joint and
several liability." Restatement (Third) of Torts: Prod. Liab. §
16 (Am. Law Inst. 1998); see Quilez-Velar v. Ox Bodies, Inc., No.
CIV. 12-1780, 2015 WL 418156, at *1, *2 (D.P.R. Feb. 2, 2015).
Neither party has challenged this predicate conclusion of law. We
invite the Puerto Rico Supreme Court to weigh in on this point, if
it chooses to do so, in the course of answering our certified
question.


                                    - 19 -
             Quilez disputes both steps in the court's reasoning.

Quilez argues that the cap on municipal damages at issue here is

not analogous to the workmen's compensation statute's remedial

restriction in Cortijo Walker.           This view, according to Quilez,

finds some support in the statutory text.         The statutory scheme in

Cortijo Walker was a workmen's compensation scheme barring all

tort actions against covered employers.           See Cortijo Walker, 91

P.R. at 560 (quoting the Workmen's Accident Compensation Act of

1935, § 20, which established that compensation under the Act

"shall be the only remedy against the employer").               In contrast,

the municipal damages cap codified at P.R. Laws Ann. tit. 21,

§ 4704 permits liability in "[c]laims against municipalities for

personal or property damages caused by the fault or negligence of

the municipality" up to a certain amount, in this case up to the

"the collectible indemnity actually provided" by the Municipality

of San Juan's insurance policy, P.R. Laws Ann. tit. 26, § 2004.

See Quilez-Velar, 2015 WL 898255, at *2 n.2.            Other jurisdictions

have recognized this type of municipal damages cap as a partial

waiver of sovereign immunity.            See, e.g., Morris v. Mass. Mar.

Acad.,   565   N.E.2d   422,   428    (Mass.   1991)    ("The   [governmental

liability] limitation is contained in the same sentence in which

sovereign immunity is waived. . . . The cap is one term of the

waiver.").     In this case, there is an argument that because the

municipal    damages    cap   operates    differently    than   the   remedial


                                     - 20 -
restriction in the workmen's compensation statute by permitting

suits up to a certain amount of damages, Ox Bodies is able to seek

at least partial contribution from the Municipality of San Juan.

It   is    notable   that   the   Municipality        of   San   Juan   has   acted

consistent with this view, including by depositing its insurance

policy limit with the Puerto Rico court.               Even while ruling that

Ox Bodies lacked a right of contribution against the Municipality

of San Juan, the magistrate judge noted that "[t]heoretically, Ox

Bodies could seek contribution from the municipality up to the

limits of its insurance policy."          Quilez-Velar, 2015 WL 898255, at

*2 n.4.14

             Ox   Bodies    counters    that    the   municipal     cap   and   the

workmen's     compensation        remedial      restriction      provision      are

materially indistinguishable.           It points to the magistrate judge's

reading of Cortijo Walker as holding that where a statute precludes

a party's liability, a third-party claim against that party is

prohibited because it "would amount to doing indirectly what the

lawmaker has forbidden to be done directly."                 Cortijo Walker, 91

P.R. at 564.      In Ox Bodies' view, the magistrate judge correctly

interpreted the municipal damages cap here as a legislative policy



      14  At oral argument, Ox Bodies conceded this point, but
then argued that nonetheless, "there is no right of contribution
for the portion of the damages allocated to the Municipality for
which the plaintiffs are asking the court to hold Ox Bodies
liable."


                                       - 21 -
choice to "protect[] . . . the municipal fisc" and any right to

contribution as a forbidden attempt to indirectly get at that fisc.

See Quilez-Velar, 2015 WL 898255, at *2.

            Quilez suggests that Ox Bodies has misunderstood Cortijo

Walker's reasoning, suggesting that the quoted language is dicta,

and   the   court's   holding   actually   resides   in   the   preceding

paragraph. There, the Cortijo Walker court reasoned that the right

to contribution was lacking because under the particular statutory

scheme -- the workmen's compensation statute -- "[t]he employer is

not liable to the workman in tort," and so "he cannot be a joint

tortfeasor with the third person and third-party plaintiff."          91

P.R. at 564. The court explained that the defendant lacked a right

of contribution against the plaintiff's employer because "[t]he

workman's claim or remedy against his employer is solely for the

statutory benefits; his claim against the third party is for

damages.    Both causes of action are in law different in kind and

they cannot result in a common legal liability."            Id.    Quilez

argues that Cortijo Walker's reasoning is inapposite, as the action

here against Ox Bodies and the third-party action against the

Municipality of San Juan both seek damages based in tort; the

magistrate judge has determined the Municipality of San Juan to be

a joint-tortfeasor, see Quilez-Velar v. Ox Bodies, Inc., No. CIV.

12-1780, 2015 WL 418156, at *2 (D.P.R. Feb. 2, 2015); Quilez-

Velar, 2015 WL 898255, at *2, and Ox Bodies has not contested that


                                 - 22 -
ruling.     Quilez   suggests      that   practical    inability   to   obtain

contribution -- here because of a deposit with the Puerto Rico

court that only by happenstance preceded judgment in the federal

suit -- poses a legal question concerning proper allocation of

risk of non-payment from a liable defendant, not concerning whether

Ox Bodies is unable to seek contribution because of some kind of

immunity.

            Quilez also views the magistrate judge's subsequent

reliance on Widow of Andino and Rosario Crespo for the rule that

a   "defendant   should    be    held   liable   for   the   damage   only   in

proportion to its fault," Widow of Andino, 93 P.R. at 180; see

Rosario-Crespo, 94 P.R. at 813, as misplaced.15 See Quilez-Velar,

2015 WL 898255, at *2.          Quilez asserts that Puerto Rico case law

almost always prioritizes a plaintiff's recovery through joint and

several liability.        Joint and several liability is "[t]he well-



      15  The magistrate judge stated that "[i]t should be noted
that the Supreme Court's holdings in Widow of Andino and Rosario-
Crespo were not based on any language in the workers' compensation
statute."   Quilez-Velar, 2015 WL 898255, at *2.    Both Widow of
Andino and Rosario Crespo explicitly rely on Cortijo Walker's
reading of the workmen's compensation statute as not permitting an
employer to be held liable in explaining why a defendant should be
held liable only for its proportion of fault. See Rosario-Crespo,
94 P.R. at 812–13; Widow of Andino, 93 P.R. at 179–80 (discussing
the operation of workmen's compensation employer remedial
restriction to "absolute[ly]" preclude recovery from the employer,
before holding that "[i]n view of the foregoing, and of the fact
that this case is governed by the special Act on the matter,
defendant should be held liable for the damage only in proportion
to its fault").


                                    - 23 -
known rule."   Szendrey v. Hospicare, Inc., 2003 TSPR 18, 2003 WL

751582 (P.R. Feb. 14, 2003); see Ruiz-Troche, 161 F.3d at 87

(applying Puerto Rico law); Ramos v. Caparra Dairy, Inc., 16 P.R.

Offic. Trans. 78, 81–82 (1985). Quilez acknowledges that the right

to contribution establishes that "the onerous effect between the

joint tortfeasors should be distributed in proportion to their

respective degree of negligence," Szendrey, 2003 WL 751582, but,

in the usual case, Quilez argues, the risk of non-payment of one

debtor is placed on the defendants, not the plaintiff, id.     The

theory is that even if Ox Bodies lacks a right of contribution --

either in fact or in law -- the general rule of joint and several

liability should apply.   No Puerto Rico Supreme Court case cited

by the parties resolves this issue, which the parties also concede.

          Ultimately, "we lack 'sufficient guidance to allow us

reasonably to predict' which of our . . . options the Puerto Rico

Supreme Court would choose," Carrasquillo-Ortiz v. Am. Airlines,

Inc., 812 F.3d 195, 199–200 (1st Cir. 2016) (quoting Pagán-Colón,

697 F.3d at 18).   Because the allocation of risk is an important

question of Puerto Rico tort law, it is determinative of the appeal

at issue, and the precedents available are not clear, we think the

better course is to certify the question in accordance with the

rules of the Puerto Rico Supreme Court.




                              - 24 -
                                 IV.

          We affirm the magistrate judge's decision to admit the

testimony of Quilez's expert.   We direct entry of judgment against

Ox Bodies' appeal.

          As to Quilez's appeal, we hereby certify to the Supreme

Court of Puerto Rico the following question:

          Was the magistrate judge correct in this case
          to limit the damages against Ox Bodies to
          $1,200,000 and deny Quilez a joint and several
          damages award of $6,000,000 against Ox Bodies?

We welcome the opinion of the Puerto Rico Supreme Court on any

other aspect of Puerto Rico law that the Justices believe should

be clarified in order to assist in the resolution of the certified

question or to give context to their reply.

          The Clerk of this court is directed to forward to the

Supreme Court of Puerto Rico, under the official seal of this

court, a copy of the certified question and this opinion, along

with a copy of the briefs and appendices filed by the parties.   We

retain jurisdiction over Quilez's appeal pending that court's

determination.




                                - 25 -
