Bartley v. Euclid, Inc. , 158 F.3d 261 ( 1998 )


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  •                     Revised November 3, 1998
    UNITED STATES COURT OF APPEALS
    FOR THE FIFTH CIRCUIT
    No. 97-40365
    JOHN BARTLEY, MIKE RUCKER, CHRIS LUKER,
    WALTER HENRY, and TIM HUMBER,
    Plaintiffs/Appellees/Cross-Appellants,
    PLANET INSURANCE COMPANY,
    Intervenor Plaintiff/Appellee,
    VERSUS
    EUCLID, INC., et al.,
    Defendants,
    EUCLID, INC.
    Defendant/Intervenor Defendant/Appellant/Cross-Appellee.
    Appeals from the United States District Court
    for the Eastern District of Texas
    October 20, 1998
    Before REAVLEY, DeMOSS and PARKER, Circuit Judges.
    ROBERT M. PARKER, Circuit Judge:
    The appeal in this diversity case challenges a jury verdict
    and resulting judgment awarding four plaintiffs a total of $2.8
    1
    million, exclusive of prejudgment and post-judgment interest, on
    products liability and negligence theories against a manufacturer
    of coal hauling vehicles. The plaintiffs cross-appeal to challenge
    the jury finding that their own negligence contributed to their
    injuries.      We affirm.
    I. PROCEEDINGS
    Between May and October 1994, plaintiffs John Bartley1, Mike
    Rucker, Chris Luker, Walter Henry and Tim Humber sued Euclid and
    others asserting personal injury/products liability claims under
    Texas   law.      The    suits   were   filed    in   federal    court    invoking
    diversity jurisdiction pursuant to 
    28 U.S.C. § 1332
    .                In December
    1995, the district court sua sponte consolidated these actions.
    Euclid’s motions for summary judgment, challenging the admission of
    plaintiffs’ expert testimony on the basis of Daubert v. Merrell Dow
    Pharms., Inc., 
    509 U.S. 579
     (1993), were denied, and the case was
    tried to a jury.        The district court entered judgment on the jury’s
    verdict which found, inter alia, that Euclid’s coal haulers were
    defective; that both Euclid and the plaintiffs were negligent; and
    that    the    coal   haulers    caused       injuries   and    damages    to   the
    plaintiffs.
    II. FACTS
    Euclid designs, builds, and markets heavy equipment including
    1
    John Bartley advised this court that he has settled his claim
    and withdrawn his appeal.
    2
    120-ton vehicles used for hauling coal at open pit coal mines.
    Initially, Euclid’s coal haulers were built with the engine mounted
    in front of the operator’s cab, which design was termed “long-
    nosed.”2     In the mid-1970's, a new design, termed “short-nosed”
    because its engine was moved back on the chassis so that it rested
    partially under the operator’s cab, was introduced.3                The new
    design differed from the earlier model in other ways, including
    using a shorter wheel base, and a trailing arm suspension system
    with rubber struts instead of steel springs.           The short-nosed coal
    haulers, which are the subject of this litigation, have better
    visibility from the driver’s seat and better maneuverability, but
    a considerably rougher ride.
    Plaintiffs, males ranging in age from 32 to 46 years, were all
    employees of Texas Utilities Mining Company (“TUMCO”) and operated
    Euclid short-nosed coal haulers in the course and scope of their
    employment.     They brought suit against Euclid claiming that they
    had    sustained   back   injuries   as   a   consequence    of   long   term
    repetitious     trauma    and   severe    vibrations    experienced      while
    operating Euclid’s short-nosed coal haulers.
    III. ADMISSIBILITY OF EXPERT WITNESS TESTIMONY
    a. Standard of review
    Euclid contends that the district court abused its discretion
    2
    Euclid’s long-nosed coal hauler is model 208 LDT.
    3
    Euclid’s short-nosed coal hauler is model 322 NDT.
    3
    and violated its gate-keeping responsibilities under Daubert v.
    Merrell Dow Pharmaceuticals, Inc., 
    509 U.S. 579
     (1993) by admitting
    the plaintiffs’ expert testimony. We review district court rulings
    on the admission of expert testimony for abuse of discretion.          See
    General Elec. Co. v. Joiner, ___U.S.___, 
    118 S. Ct. 512
    , 517
    (1997); see also Moore v. Ashland Chemical, Inc., ___F.3d___ (5th
    Cir. 1998)(en banc).
    b. District court ruling
    Plaintiffs’ experts fall into two categories.           Dr. Charles
    Aprill, Dr. Richard Bunch and Dr. Kelvin Samaratunga had formal
    training in the medical and physical therapy fields and were called
    to testify concerning causation.          Arthur Chaseling and Geoff
    McDonald have formal training in the field of engineering and were
    called to testify regarding alleged design defects and potential
    alternative designs.    The district court specifically found that
    both groups possessed sufficient qualifications to be considered
    experts, that their proffered evidence was reliable and relevant
    and that the probative value of the evidence was not “substantially
    outweighed by any type of prejudice.”
    The   district   court   first   considered   whether   the   experts
    satisfied the requirements set out by Federal Rule of Evidence 702
    and Daubert v. Merrell Dow Pharmaceuticals, Inc., 
    509 U.S. 579
    4
    (1993).4
    The Federal Rules of Evidence provide:
    Rule 702. Testimony by Experts
    If scientific, technical, or other specialized knowledge
    will assist the trier of fact in issue, a witness
    qualified as an expert by knowledge, skill, experience,
    training, or education, may testify thereto in the form
    of an opinion or otherwise.
    The district court began its analysis by acknowledging that, under
    Texas law, plaintiffs’ medical causation evidence, as well as the
    engineering evidence, are subject to the standards set out by the
    Supreme Court in Daubert.
    The district court listed the non-exclusive Daubert factors
    which it applied: 1) whether a theory or technique can be or has
    been tested; (2) whether the theory has been subjected to peer
    review and publication; (3) whether a potential rate of error has
    been   established;   and   (4)   whether   the   theory   is   “generally
    accepted” within the scientific community.        See Daubert, 
    509 U.S. at 593-94
    . The district court then cited United States v. Downing,
    
    753 F.2d 1224
     (3rd Cir. 1985) in support of three additional
    factors that the district court found instructive to a reliability
    4
    In January 1997, when the district court ruled on this motion,
    the Fifth Circuit had not squarely addressed whether Daubert
    applied to “non-scientific” expert testimony. The district court
    noted that uncertainty, but found it to be of no consequence to the
    determination of the motion, because all of the experts satisfied
    the requirements of Daubert. The subsequent decision in Watkins v.
    Telsmith, Inc., 
    121 F.3d 984
     (5th Cir. 1997), holding that Daubert
    is not limited to “scientific knowledge,” is therefore satisfied by
    the district court’s analysis.
    5
    determination:(1) the existence of a body of literature dealing
    with a particular topic or technique; (2) the qualifications and
    professional stature of the witness in question; and (3) the
    relationship of the current theory to other methods of analysis.
    c. Causation experts
    Euclid specifically challenges the district court finding that
    Plaintiffs’ causation experts offered reliable evidence.
    Dr.   Aprill,   a   medical   doctor   specializing    in    diagnostic
    radiology, evaluated Plaintiffs’ spinal problems and researched the
    cause of those problems.         Aprill’s research involved comparing the
    Magnetic Imaging Resonance (“MRI”) scans of 90 individuals who
    drove the coal haulers that are the subject of this case with the
    MRI scans of 80 back pain patients, age and sex matched to the
    hauler drivers.        Aprill employed mainstream scientific research
    techniques to preclude bias in his conclusions.               These included
    Aprill reading MRIs without knowing whether the scans were taken
    from   hauler   drivers     or   from   the   control    group,    as    well   as
    intraobserver reliability checks by which a colleague selected
    random MRIs for double readings without Aprill’s knowledge.                     He
    also testified concerning the results of another study of endplate
    fractures conducted in Minneapolis, finding that the MRIs of 38% of
    asymptomatic     Minneapolis      subjects    revealed     broken       endplates
    compared to 41% in his study.
    Aprill concluded that the MRIs of the hauler driver group
    6
    demonstrated multiple endplate fractures at multiple levels in the
    dorsal and lumbar spines and that accelerated disc degeneration
    occurred more often and at more levels in the hauler driver group
    than in the comparable group of people with back pain.                    He termed
    this finding statistically significant.               The multiple endplate
    fractures demonstrated by the coal hauler population suggested to
    Aprill that those individuals were subject to repetitive vertical
    compression resulting in fractured endplates.                Aprill’s opinions
    were   supported    by    an   article    appearing   in     1992    in   Clinical
    Biomechanics, stating that exposure to whole body vibrations causes
    structural damage to the endplate and subchondral bone.                      Aprill
    stated that he found this “fingerprint” condition throughout the
    hauler driver population.            Although endplate abnormalities are
    fairly common, the drivers had not only more end plate fractures
    than the control population, but also an uncommon distribution of
    these fractures.         Specifically, Aprill testified that in mature
    human populations most injuries appear in the lumbar (lower back)
    region,    with   cervical       (neck)   injuries   next    and    dorsal   spine
    injuries a distant third.           The number of dorsal injuries Aprill
    found in the hauler driver population was very unusual.                   Further,
    the control group included individuals who had exposure to other
    risk factors identified by Euclid as possibly causing Plaintiffs’
    back injuries, including being over-weight, smoking, and truck
    driving.     However,      the    significant   number      and    characteristic
    7
    distribution of injuries pointed to hauler driving as the single
    risk factor resulting in the “fingerprint” injuries which showed up
    in Aprill’s study.
    Dr. Samaratunga, the plaintiffs’ treating neurosurgeon, relied
    partially   on    Aprill’s   MRI   study    for   his   conclusion   that   the
    endplate fractures were caused by whole body vibrations.                    Dr.
    Bunch, a physical therapist and ergonomics expert, testified that
    he had performed an ergonomic assessment of the coal haulers and
    concluded that the coal haulers contributed to the plaintiffs’
    injuries.
    The district court, after reviewing the curriculum vitae of
    Dr. Aprill, Dr. Samaratunga and Dr. Bunch, found that each of these
    witnesses met the requirements of Rule 702 for designation as
    expert witnesses in this matter.             In addition to the doctors’
    credentials, the court noted that there is a body of literature
    dealing with repetitive trauma back injuries, the doctors’ theories
    can be tested, and that the methodology that the doctors used
    derived from other accepted methodologies.              Based on these facts,
    the district court determined that the testimony was reliable under
    the standards set forth in Daubert.
    Euclid      attacks   the   district    court’s     finding   that   these
    causation experts provided reliable testimony.                 First, Euclid
    contends that the “mere existence” of a body of literature on a
    given subject does not speak to the question of reliability.
    8
    Second, they point out that the qualifications and professional
    stature of a witness, standing alone, do not evidence reliability.
    Third, they complain that the district court’s conclusion that the
    experts’ theories are “derived from methodology which relates to
    other   accepted   methodologies”   is   not   helpful   in   determining
    reliability. Finally, they list those Daubert factors which do not
    point to reliability in this case: the potential rate of error in
    the causation witnesses’ work was not established, the “general
    acceptance” of their conclusions was not established, and Dr.
    Samaratunga was allowed to testify concerning causation, when his
    area of expertise was established as treatment of back pain, not
    etiology.
    Given the broad discretion vested in trial courts to “keep the
    gate” for the purpose of admitting or excluding opinion testimony,
    we cannot say that the district court abused its discretion in this
    case.   See Moore v. Ashland Chemical, Inc., ___ F.3d ___ (5th Cir.
    1998)(en banc).    Euclid asserts that each factor, standing alone,
    may not have been enough to support the admission of opinion
    testimony.   However, the district court considered the Daubert
    factors in the aggregate, and determined that, on balance, the
    experts’ opinions were sufficiently reliable to merit admission
    into evidence and testing in the fire of cross examination and
    contrary evidence.    We find that the district court did not abuse
    its broad discretion in that exercise.     See General Electric Co. v.
    9
    Joiner, ___ U.S. ___, 
    118 S. Ct. 512
    , 517 (1997); see also Moore v.
    Ashland Chemical, Inc., ___ F.3d___ (5th Cir. 1998)(en banc).
    c. Liability experts
    Although    Euclid   generally    complains   of    the   admission    of
    testimony by liability experts McDonald and Chaseling, the only
    basis for the challenge advanced on appeal concerns the manner by
    which Chaseling measured the vibration levels in the coal haulers.
    Euclid contends on appeal, as it did at trial, that it was
    inappropriate for Chaseling to measure the vibrations in the coal
    haulers by attaching an accelerometer to the metal frame below the
    seat.   Chasling responded to that contention, testifying that,
    pursuant to International Standards Organization (“ISO”) standards,
    it is permissible to measure the vibrations from the frame rather
    than from the seat as long as the transmission characteristics of
    the seat cushion are taken into account when calculating the actual
    vibration.      Chasling testified further that he believed that
    measuring the vibration from the frame gave better comparable
    results from truck to truck because the condition of the seating
    material varies widely.
    Euclid     also   complains    that    Chaseling     turned    on     the
    accelerometer in 16-second bursts only when told to do so by people
    who were     suing   Euclid,   gathering   less   than   seven   minutes    of
    vibration data over a fifteen hour span of time, which resulted in
    vibration data that was unreliable. Chaseling explained during his
    10
    testimony that he was attempting to record vibration measurements
    when the hauler was in a loping mode.        For this he relied on the
    input of the hauler drivers to advise him when they felt the
    machine phase into that mode.
    The district court noted that, “[a]s a general rule, questions
    relating to the bases and sources of an expert’s opinion affect the
    weight to be assigned that opinion rather than its admissibility
    and should be left for the jury’s consideration.”         Viterbo v. Dow
    Chemical Co., 
    826 F.2d 420
    , 422 (5th Cir. 1987).          The question for
    the district court was whether the “analytical gap” between the
    causation   opinion   offered   by   the   expert   and   the   scientific
    knowledge and available data advanced to support that opinion is
    too wide.   Moore v. Ashland Chemical Inc.,           F.3d       (5th Cir.
    1998). Here the district court determined that it was not.
    [T]hese witnesses’ theories can be tested, their
    qualifications are adequate, literature exists dealing
    with common design principals and methodologies for
    testing such designs, and the methods from which these
    opinion were reached are related to other methodologies
    and theories in the area of engineering safety and
    design. In the Court’s opinion, these factors render
    this evidence reliable under Daubert.
    Memorandum Opinion and Order, January 2, 1997, at 6.            We conclude
    that the district court did not abuse its discretion in finding
    that the expert testimony offered by Chaseling and McDonald was
    reliable and relevant and therefore admissible, and that it was
    within the province of the jury to weigh the credibility of that
    evidence in light of Euclid’s criticism that Chasling’s methods for
    11
    testing vibration levels yielded inaccurate results.
    IV. SUFFICIENCY OF THE EVIDENCE
    Euclid moved for judgment as a matter of law based on the
    insufficiency of the evidence to support the plaintiffs’ products
    liability and negligence claims.             The district court denied the
    motion. We review that ruling de novo, applying the same standards
    employed by the district court.          See Gutierrez v. Excel Corp., 
    106 F.3d 683
    , 686 (5th Cir. 1997). “All evidence with all reasonable
    inferences must be considered in the light most favorable to the
    nonmoving party.”     
    Id.
        Judgment as a matter of law should have
    been granted if there was “no legally sufficient evidentiary basis
    for a reasonable jury to find for” the plaintiffs on issues they
    bore the burden of proving.       FED.R.CIV.P. 50(a).
    The   jury   found   that   the    preponderance   of   the   evidence5
    established that there were design and marketing defects in the
    coal haulers at the time they left the possession of Euclid that
    were a producing cause of the plaintiffs’ injuries.           The jury also
    found that the preponderance of the evidence established that
    negligence by both Euclid and the plaintiffs proximately caused the
    injuries in question. On appeal, Euclid challenges the sufficiency
    5
    The district court instructed the jury that all claims in this
    case must be established by a preponderance of the evidence, which
    “means evidence that persuades you that the plaintiffs’ claims are
    more likely true than not true.”     Charge to the Jury, at 11.
    Neither party challenges the district court’s articulation of the
    applicable burden of proof.
    12
    of the evidence as to design defects, marketing defects, Euclid’s
    negligence and causation.
    a. Strict liability design defect
    In determining whether a product is defectively designed, “the
    jury must conclude that the product is unreasonably dangerous as
    designed, taking into consideration the utility of the product and
    the risk involved in its use.”              American Tobacco Co., Inc. v.
    Grinnell, 
    951 S.W.2d 420
    , 432 (Tex. 1997).            Liability for a design
    defect may attach even if the defect is obvious or apparent.
    Turner v. General Motors Corp., 
    584 S.W.2d 844
    , 850 (Tex. 1979).
    Whether a product has a design defect is evaluated in the light of
    economic     and   scientific      feasibility   of    safer   alternatives.
    Boatland of Houston, Inc. v. Bailey, 
    609 S.W.2d 743
    , 756 (Tex.
    1980).
    We find no merit in Euclid’s argument that the evidence is not
    sufficient    to   support   the    jury’s   verdict   because   plaintiffs’
    experts did not use the words “unreasonably dangerous.”             Although
    an expert may testify to an ultimate issue, such testimony is not
    required to support the jury’s verdict.            See FED.R.EVID. 704(a).
    Rather, we must look to all the evidence, drawing all reasonable
    inferences in favor of the plaintiffs in evaluating the sufficiency
    of the evidence.     See Crosthwait Equipment Co., Inc. v. John Deere
    Co., 
    992 F.2d 525
    , 528 (5th Cir. 1993).
    Chasling testified that the vibration of the hauler violated
    13
    the   health   and     safety       thresholds    of   International    Safety
    Organization (“ISO”) Standard 2631.6              Under that standard, the
    hauler drivers should not be exposed to vibrations in excess of
    established levels for more than 1.6 hours in a 24 hour period.
    The plaintiffs were routinely exposed to vibrations in excess of
    ISO standards for a majority of their 8 to 12 hour shifts.               It was
    not simply the intensity of the vibrations but the vector of forces
    caused by a combination of vertical and longitudinal vibrations
    that produced injury.        Evidence supports a determination that the
    “geometry” of the short-nose haulers, i.e. the shorter wheel base
    and   placement   of   the    engine,    caused    the   vibrations.     Those
    vibrations were exacerbated by the substitution of rubber struts
    for the steel springs which had been used in the long-nose haulers.
    The evidence identified Euclid’s own long-nose hauler as a safe,
    feasible   alternative       from    both    an   engineering   and    economic
    perspective. Euclid focuses on evidence that the short-nose design
    was a response to user demand for better maneuverability and
    visibility, arguing that such demand made the older design obsolete
    and therefore non-feasible.          While Euclid’s line of reasoning was
    6
    Euclid points out that the ISO standards are not laws nor
    regulations, but are voluntary consensus standards for evaluation.
    Therefore, they contend, without specifically challenging the
    admission of evidence concerning ISO standards, that their failure
    to comply with the standards is not relevant to the issues in this
    case. However, evidence concerning ISO standards was before the
    jury, and we conclude that such evidence was relevant and the jury
    was free to assign whatever weight to the evidence that they
    determined was appropriate.
    14
    certainly relevant, this court is not empowered to sit as a super
    jury, substituting its view for the jury’s assessment of the weight
    and credibility to assign to the conflicting feasibility evidence.
    See Gutierrez v. Excel Corp., 
    106 F.3d 683
    , 687 (5th Cir. 1997).
    Based on the foregoing, we find that the evidence before the
    jury was sufficient to support its conclusion that the short-nosed
    coal haulers are unreasonably dangerous as designed.
    b. Negligence: marketing defect, failure to warn.
    Euclid challenges on appeal the jury’s determination that
    there was a defect in the marketing of the coal haulers at the time
    these products left the possession of Euclid.
    Under   Texas    law,   negligence    consists    of    four   essential
    elements: (1) a legal duty owed to the Plaintiff by the Defendant;
    (2) a breach of that duty; (3) an actual injury to the Plaintiff;
    and (4) a showing that the breach was a proximate cause of the
    injury.    See Williams v. Southern Pacific Transp. Co., 
    804 S.W.2d 132
    , 138 (Tex. App.--Houston [1st Dist.] 1990, writ denied). While
    strict    liability   focuses   on   the   condition    of    the    product,
    negligence looks at the acts of the manufacturer and determines if
    it exercised ordinary care in designing and producing its product.
    American Tobacco Co., Inc. v. Grinnell, 
    951 S.W.2d 420
    , 437 (Tex.
    1997).
    A product may be unreasonably dangerous because of a defect in
    marketing.    See Caterpillar, Inc. v. Shears, 
    911 S.W.2d 379
    , 382
    15
    (Tex.   1995).      A    defendant’s   failure   to   warn   of   a   product’s
    potential dangers when warnings are required is a type of marketing
    defect.   See 
    id.
           A manufacturer has a duty to warn if it knows or
    should know of the potential harm to a user because of the nature
    of its product.         See American Tobacco Co., Inc. v. Grinnell, 
    951 S.W.2d 420
     (Tex. 1997).          Euclid contends that the evidence was
    insufficient to support the jury’s verdict that the short-nosed
    haulers were unreasonably dangerous and that Euclid knew or should
    have known of a potential harm to users because of the nature of
    its product.      Euclid does not dispute that it failed to warn
    plaintiffs of unreasonably dangerous characteristics of its short-
    nose haulers.
    A manufacturer has a duty to test and inspect his product to
    uncover scientifically discoverable dangers before the product is
    sold. See Owens-Corning Fiberglas Corp. v. Malone, 
    916 S.W.2d 551
    ,
    562 (Tex.App.--Houston [1st Dist.], 1996, writ granted). A product
    must not be made available to the public without disclosure of
    those dangers that the application of reasonable foresight would
    reveal. See 
    id.
             There is evidence in the record that Euclid never
    ride-tested the short-nosed hauler before placing it on the market.
    In 1978, after an Australian purchaser complained about the rough
    ride of its short-nosed hauler, Euclid performed some ride tests
    specifically on the Australian hauler and found the ride to be
    unacceptable.     However, the short-nosed haulers were still not
    16
    tested by Euclid in accordance with ISO procedures or otherwise,
    even though Euclid’s chief engineer admitted that he was aware of
    the ISO procedures for whole body vibration testing.                 Euclid made
    no design changes in response to the reports made after the
    Australian testing, and even canceled its Ride Improvement Program.
    Further, there was evidence that Euclid knew or should have
    known that three people sustained injuries caused by the rough ride
    of the short-nosed hauler sold to the Australian mine. Euclid took
    the position that the complaints were limited to one machine in
    Australia.         The district court admitted into evidence a letter
    which had been sent to Morgan Equipment, an authorized Euclid
    dealer, which referenced “3 recent injuries (1 compensatable)
    claimed to be caused by the rough ride of” the Euclid short-nosed
    hauler.       The letter also references “representations by the union
    on       driver   discomfort....”    Euclid    contends    that   this   is   not
    evidence of Euclid’s negligence because there is no evidence that
    anyone at Euclid saw the letter and because it is not clear that
    the injuries referred to in the letter were same type injuries
    experienced by plaintiffs in this case.              Euclid acknowledges that
    they were aware that the Australian short-nosed hauler had an
    unacceptably        rough   ride7,   but    points   to   evidence    that    the
    7
    John Stoneman, the managing director of Morgan Equipment
    Company, the Euclid dealer that sold the short-nosed hauler to the
    Australian mine, testified concerning the lengthy history of
    attempts by both Morgan and Euclid to determine the cause of and to
    remedy the ride problems in the Australian hauler.
    17
    Australian hauler was a “lemon,” and that it was specially modified
    to the customer’s specifications, operated on rougher roads, and
    that these differences between the Australian hauler and the Texas
    haulers excused Euclid from warning the Texas buyers about the
    Australia rough ride problems.
    The trial record contains evidence upon which a rational jury
    could base a rejection of Euclid’s position.           Euclid entered into
    a contract with Battelle Laboratories in February 1978, later
    expanded in May 1978, under which Euclid would pay $17,500 to
    Battelle to solve the “ride problem” in its short-nosed haulers.
    Euclid also initiated a Ride Improvement Program during 1978, which
    was later discontinued.      These efforts, combined with the letter
    and the failure to test the equipment prior to marketing is
    sufficient to support the jury’s conclusion that Euclid knew or
    should have known of the potential harm to users because of the
    rough ride problems of the short-nosed haulers.
    c. Causation
    Causation   is   an   element   of   both   the   plaintiffs’   strict
    products liability claims and their negligence claims.           See Union
    Pump Co. v. Allbritton, 
    898 S.W.2d 773
    , 775 (Tex. 1995).             Strict
    liability requires proof of a producing cause, while proximate
    cause is the test in negligence actions.         See General Motors Corp.
    v. Saenz, 
    873 S.W.2d 353
    , 357 (Tex. 1993).
    A producing cause is an “exciting or contributing cause which
    18
    in       the    natural     sequence,    produced     the       injuries    or    damages
    complained of.” Haynes & Boone v. Bowser Bouldin, Ltd., 
    896 S.W.2d 179
    , 181 (Tex. 1995).
    Proximate cause, on the other hand, consists of both cause in
    fact and foreseeability.                See Union Pump Co. v. Albritton, 
    898 S.W.2d 773
    ,   775   (Tex.   1995).        Cause    in    fact   means     that    a
    defendant’s acts or omissions were a substantial factor in bringing
    about a plaintiff’s injury.               
    Id.
         Foreseeability is satisfied by
    showing that the actor, as a person of ordinary intelligence,
    should have anticipated the danger to others by his negligent act.
    See McClure v. Allied Stores of Tex., Inc., 
    608 S.W.2d 901
    , 903
    (Tex.      1980).         Foreseeability     does    not    require     the      actor   to
    anticipate the particular accident, but only that he reasonably
    anticipate the general character of the injury. See El Chico Corp.
    v. Poole, 
    732 S.W.2d 306
    , 313 (Tex. 1987).8
    There need not be direct proof of causation.                     The jury may
    infer proximate cause from the surrounding circumstances.                                See
    Mosley v. Excel Corp., 
    109 F.3d 1006
    , 1009 (5th Cir. 1997).                          If a
    negligent act actively aids in producing an injury, it need not be
    the sole cause, but it must be a concurring cause, and such as
    might reasonably have been contemplated as contributing to the
    8
    Producing cause requires a lesser burden than proximate cause
    because it does not require foreseeability. Purina Mills, Inc. v.
    Odell, 
    948 S.W.2d 927
    , 935 (Tex.Civ.App. - Texarkana 1997, writ
    denied).
    19
    result.   See McClure, 608 S.W.2d at 904.        However, causation “must
    be established by probative evidence, not by mere conjecture or
    guess.”   Gutierrez v. Excel Corp., 
    106 F.3d 683
    , 687 (5th Cir.
    1997).
    The question for this court is whether there was sufficient
    evidence to support the jury’s conclusion that Plaintiffs’ back
    injuries were, more likely than not, caused by driving Euclid’s
    coal haulers.      Of course, there is not a precise fit between
    science and the applicable legal burdens of proof.          However, when
    the incidence of a disease or injury is sufficiently elevated due
    to exposure to a purported source of injury, a plaintiff can raise
    a fact question on causation by presenting evidence that he was
    exposed to that substance and exhibits the disease or injury.           See
    Merrell Dow Pharms., Inc. v. Havner, 
    953 S.W.2d 706
     (Tex. 1997),
    citing Daubert v. Merrell Dow Pharms., Inc., 
    43 F.3d 1311
    , 1320 n.
    13 (9th Cir. 1995)(on remand).       The question remains what quantum
    of elevation is sufficient to satisfy the preponderance of evidence
    burden of proof.    The Texas Supreme Court seemingly answered this
    question, holding that epidemiological evidence should show that
    the risk of an injury or condition in the exposed population was
    more than double the risk in the unexposed or control population.
    Havner,   953   S.W.2d   at   716.    However,    an   intermediate   Texas
    appellate court subsequently addressing the Havner opinion takes
    the position that Havner did not “set any strict rules regarding
    20
    what types of evidence would be sufficient or not sufficient to
    support    a   finding    of    causation.”         Minnesota   Mining       and
    Manufacturing Co. v. Atterbury, ___ S.W.2d ___, ___ (Tex.App. --
    Texarkana 1998)(
    1998 WL 436916
     at *15).             There is no requirement
    that a party must have reliable epidemiological evidence of a
    relative risk of 2.0 or greater.              
    Id.
         Reliable evidence of
    relative   risk   less   than   2.0   can   be   considered,    but   must    be
    supported by other credible, reliable evidence of causation.                 
    Id.
    Further, epidemiological evidence with a relative risk of 2.0 or
    greater does not automatically pass a sufficiency review.                
    Id.
    Assuming, without deciding, that Havner’s rule controls,9 the
    evidence before the jury more than satisfies the relative risk of
    2.0 standard.     According to Aprill’s testimony, the plaintiffs’
    condition is revealed in their MRIs as a “fingerprint” of a
    characteristic number and distribution of end plate fractures which
    is essentially unique to hauler drivers.            While 68% of the control
    9
    Havner amounts to the Texas Supreme Court’s definition of “more
    likely than not burden of proof.” See Havner, 953 S.W.2d at 717.
    Arguably, the definition of the applicable burden of proof is
    procedural rather than substantive, and therefore controlled by
    federal rather than state law.       See Gasperini v. Center for
    Humanities,   Inc.,   
    518 U.S. 415
    ,   426   (1996)(noting  that
    classification of a law as “substantive” or “procedural” is
    “sometimes a challenging endeavor.”) The Fifth Circuit has not
    weighed in on the question of whether evidence must show more than
    doubling of the risk to support a jury’s finding of causation. The
    federal circuits which have considered the question have reached
    diverse results. See Havner, 953 S.W.2d at 716 (listing cases
    demonstrating the split). The parties neither briefed nor argued
    the issue, and it is not outcome determinative in this case.
    Therefore, we decline to reach it.
    21
    group exhibited some evidence of end plate fractures, none of those
    individuals exhibited the characteristic injuries found in 90% of
    hauler drivers, that is, a pattern of back pathology discernable
    from the number, severity and distribution of end plate fractures.
    While the test formulated in Havner, if applicable, requires
    incidence      of   “fingerprint”     conditions      in     the    hauler     driver
    population      double    that   of   the   control        group,    the     evidence
    established that the fingerprint condition found in 90% of the
    hauler drivers existed in 0% of the control population.                       Aprill
    additionally testified that, on average, the hauler drivers had
    twice as many end plate fractures as the control group.                       Aprill
    explained to the jury that end plate fractures are caused by
    vertical compression stress on the spine.              If a person falls and
    lands hard on his buttocks, this may cause an individual end plate
    to crack.    Such injuries appear most often at the top of the lumbar
    spine.   However, long-term exposure to whole body vibration causes
    multiple end plate fractures throughout the spine.                    The control
    group exhibited the former pattern of end plate fractures, while
    the   hauler    drivers    exhibited    the   latter.         This    evidence    is
    sufficient to support the jury’s verdict on the issue of causation
    under the Havner standard.
    V. STATUTE OF LIMITATIONS
    a. The Texas Discovery Rule
    In Texas, a personal injury action must be filed “not later
    22
    than two years after the day the cause of action accrues . . . .”
    TEX.CIV.PRAC.&REM.CODE ANN. § 16.003(a). Generally, accrual occurs on
    the date the plaintiff first becomes entitled to sue the defendant
    based upon a legal wrong, even if the plaintiff is unaware of the
    injury.    Zidell v. Bird, 
    692 S.W.2d 550
    , 554 (Tex. App.--Austin,
    1985, no writ).
    The “discovery rule” is an exception to this general rule.
    See Moreno v. Sterling Drug, Inc., 
    787 S.W.2d 348
    , 351 (Tex. 1990).
    Under the Texas discovery rule, the accrual of a cause of action is
    deferred in cases in which the alleged wrongful act and resulting
    injury were inherently undiscoverable at the time they occurred but
    may be objectively verified.     See S.V. v. R.V., 
    933 S.W.2d 1
    , 6
    (Tex. 1996).
    Euclid asserted at trial that the statute of limitations
    barred the Plaintiffs’ claims and the issue was submitted to the
    jury. The jury found that Plaintiffs failed to file their lawsuits
    within two years of the date they first suffered injury.       The jury
    made an additional findings that 1) the plaintiffs filed their
    lawsuits within two years of the date they first knew, or in the
    exercise of reasonable diligence should have known, that their
    injuries were caused by driving the coal haulers; 2) plaintiffs’
    injuries   were   inherently   undiscoverable;   and   3)   plaintiffs’
    injuries were objectively verifiable.
    b. Standard of Review
    23
    On appeal, Euclid challenges the sufficiency of the evidence
    to   support    the   jury’s   finding   regarding   the   inherently
    undiscoverable and objectively verifiable nature of the injuries.
    Like the sufficiency of the evidence issues on liability, we review
    this ground of error by considering all evidence, drawing all
    reasonable inferences in the light most favorable to the nonmoving
    party.     Gutierrez v. Excel Corp., 
    106 F.3d 683
    , 686 (5th Cir.
    1997).    We will reverse the denial of Euclid’s motion for judgment
    as a matter of law if there was not substantial evidence “such that
    reasonable jurors might reach different conclusions...”       
    Id. at 686-87
    .
    c. Inherently undiscoverable injuries
    An injury is “inherently undiscoverable” if it is by nature
    unlikely to be discovered within the prescribed limitations period
    despite due diligence.     S.V. v. R.V., 933 S.W.2d at 7.     Euclid
    argues that because Plaintiffs were aware of a painful “back-
    slapping” sensation while driving the coal haulers, their injuries
    were immediately “discoverable.” Plaintiffs counter that, in spite
    of the uncomfortable ride, they had no reason to suspect the
    insidious damage that was occurring within their spines.          We
    conclude that the evidence was sufficient to support the jury’s
    “inherently undiscoverable” finding.     Repetitive trauma injuries
    like those at issue in this case are not readily susceptible to
    discovery at the time of a particular, individual contact. Rather,
    24
    the fractured endplates throughout the plaintiffs’ spines which
    were discovered later, were “unexpected latent injur[ies] which
    were unknown and unknowable at the time of the traumatic event.”
    See Albertson v. T.J.Stevenson & Co., Inc., 
    749 F.2d 223
    , 233 (5th
    Cir. 1984).
    d. Objectively verifiable injuries
    Euclid contends that there is not legally sufficient evidence
    to support the jury’s determination that the Plaintiff’s injuries
    were objectively verifiable.        Euclid relies on language from the
    Texas Supreme Court’s opinion in S.V. v. R.V., 
    933 S.W.2d 1
     (Tex.
    1996): “For the purpose of applying the discovery rule, expert
    testimony on subjects about which there is no settled scientific
    view . . . cannot provide objective verification of [alleged wrong
    and injury.]” 
    Id. at 18
    .      S.V. held that expert opinion regarding
    recovered memories of childhood sexual abuse could not meet the
    objective verifiability element for the Texas discovery rule.          The
    court noted the lack of consensus in the scientific community
    concerning the reliability of recovered memory, 
    id. at 17-18
    , but
    noted that expert opinion coupled with other evidence could provide
    the kind of verification required.        
    Id. at 16
    .
    Here,    the   jury   heard   evidence   that   plaintiffs   suffered
    herniated intervertebral discs and degenerated spines, confirmed by
    recognized diagnostic testing.       We hold that such evidence, which
    came in the form of testimony from medical experts, relying on long
    25
    accepted methods of reading and interpreting MRIs, is sufficient to
    support    the   jury’s   affirmative   answer   on   the   “objectively
    verifiable” nature of the injuries.
    e. Limitation bar as to Appellee Humber
    Euclid devotes a single sentence to its contention that a
    unique limitations argument bars the claim of Tim Humber because a
    doctor told him more that two years before he filed suit that
    repetitious trauma had compromised his back.          However, the jury
    heard evidence that Humber’s doctor had actually diagnosed a
    herniated disc and it was TUMCO that advised him to claim his
    injury was due to repetitive trauma disease so that an injury date
    could be established for workers’ compensation purposes.            Such
    evidence does not preclude a reasonable jury from finding that
    Humber discovered that he suffered a repetitive trauma injury less
    than two years before he filed suit or that his injury resulted
    from driving the coal haulers.
    VI. PROPORTIONATE RESPONSIBILITY10
    The district court reduced the award of damages to Plaintiffs
    as a consequence of the jury’s findings concerning Plaintiffs’
    10
    This issue is referred to in the record and in much of the
    precedential jurisprudence as “contributory negligence” or
    “comparative responsibility.” Texas law was modified in 1995 to
    its present form which refers to the same concept as “Proportionate
    Responsibility.” See TEX.CIV.PRAC.& REM. CODE ANN., Ch.33.
    26
    proportionate responsibility for their injuries.11                 A take nothing
    judgment      was   entered     as   to   Rucker   because   his   proportionate
    responsibility was found to be 70%.                Plaintiffs filed a cross-
    appeal, arguing that there is insufficient evidence to support the
    jury’s findings regarding their proportionate responsibility for
    their injuries and that they should have been granted a judgment as
    a matter of law on that issue.
    a. Was the issue preserved for appellate review?
    Initially, we must determine whether Plaintiffs preserved the
    right to appeal the jury’s proportionate responsibility findings.
    Euclid       contends    that   Plaintiffs     failed   to   comply    with   the
    requirements of FED.R.CIV.P. 50, thus precluding our review of the
    sufficiency of the evidence to support the jury’s verdict on this
    issue. Generally, sufficiency of the evidence is not reviewable on
    appeal unless a pre-verdict motion for judgment as a matter of law
    was made in the trial court at the conclusion of all the evidence.
    11
    Question No. 4. For each person or product found by you to
    have caused the injury, find the percentage caused by...
    b.        Chris Luker     30
    Euclid, Inc.    70...
    c.        Mike Rucker      70
    Euclid, Inc.     30...
    d.        Walter Henry     50
    Euclid, Inc.     50...
    e.        Tim Humber       40
    Euclid, Inc.     60....
    27
    See McCann v. Texas City Refining, Inc., 
    984 F.2d 667
    , 671 (5th
    Cir. 1993).      However, strict compliance with Rule 50 is not
    necessary so long as the purposes of the requirement have been
    satisfied. Greenwood v. Societe Francaise De, 
    111 F.3d 1239
    , 1244-
    45 (5th Cir.), cert. denied, 
    118 S. Ct. 558
     (1997).                    “These
    purposes are met when the court and the [opposing party] are
    alerted to the grounds on which the [complaining party] contends
    the evidence is insufficient prior to the submission of the case to
    the jury.”    
    Id. at 1245
    .
    In this case, the evidence closed shortly before noon on
    Thursday, January 30, 1997.           The trial court then considered
    Euclid’s motion for judgment as a matter of law and began work on
    the   jury   charge.   After   6:00    p.m.   the   following   day,   after
    completing what the court termed its “informal charge conference”
    the court allowed the parties to go on the record with “comments,
    requested instructions, and objections.”        At that time, Plaintiffs
    objected orally, on the record, to the submission of contributory
    negligence to the jury on the ground that there was not legally
    sufficient evidence to support the submission of the evidence to
    the jury.    The court overruled the objection.         After the verdict
    was returned, Plaintiffs filed a “renewed” motion for judgment as
    a matter of law addressing the sufficiency of the evidence of
    contributory negligence.
    It is undisputed that Plaintiffs failed to file a formal,
    28
    written, pre-verdict motion for judgment as a matter of law.
    However, we find that Plaintiffs’ objection to the jury charge on
    sufficiency of the evidence grounds served as the functional
    equivalent of a formal pre-verdict motion. See Greenwood, 
    111 F.3d at 1245
    , n.7 & 8; see also Wells v. Hico ISD, 
    736 F.2d 243
    , 251-52
    (5th Cir. 1984).    The issue of sufficiency of the evidence on
    plaintiffs’ proportionate responsibility is thus preserved for
    appellate review.
    b. Sufficiency of the evidence on proportionate responsibility
    Plaintiffs contend that there is no evidence that any of the
    Plaintiffs had an awareness of the cumulative trauma they were
    suffering as a result of their exposure to Euclid’s coal haulers.
    Nor, they argue, is there any evidence in the record to indicate
    that any of the Plaintiffs should have had knowledge of the
    dangerous and unsafe nature of the vibration levels they were
    receiving while driving the coal haulers.
    Euclid   answers   that   the   evidence   supports   findings   that
    Plaintiffs were negligent and at least partially responsible for
    their alleged physical injuries and damages.          Euclid points to
    evidence that the coal hauler, like any other vehicle, had a
    rougher ride when road conditions were bad and the driver was
    driving too fast.   The record contains evidence that there was no
    reason for driving the haulers at top speed and in fact TUMCO
    management wanted its drivers to slow down.          Further, there was
    29
    evidence that Rucker continued to smoke, though doctors had told
    him smoking aggravates his back injury.
    Given   evidence   that   the   Plaintiffs   knew   the   vibrations
    worsened based on the speed the haulers were driven and that the
    drivers drove the haulers faster than their employer recommended,
    we find sufficient evidence to support the proportional negligence
    findings of the jury.      Further, the evidence is sufficient to
    sustain the jury’s finding that Rucker was responsible for 70% of
    the negligence that resulted in his injuries, thereby precluding
    any obligation for Euclid to compensate him for his damages.
    VII. JURY CHARGE
    a. Euclid’s challenge to the jury charge on the issue of causation
    Concerning the causation element of Plaintiffs’ negligence
    cause of action, the district court instructed the jury that
    “[P]roximate cause” means that cause which in a natural
    and continuous sequence, unbroken by any new and
    independent cause, produces an event without which that
    event would not have occurred, and which event or some
    similar event should have been foreseen by a person in
    the exercise of ordinary care under the same or similar
    circumstances . . . .
    The district court separately defined the causation element of
    the Plaintiffs’ products liability cause of action:
    “[P]roducing cause” as used in these instructions, means
    an efficient, exciting, or contributing cause, which in
    a natural and continuous sequence, produces the injury in
    question . . . .
    Euclid complains that the district court did not accept its
    proposed jury instruction that in order to impose liability on
    30
    negligence or products liability claims, the jury must determine
    that Euclid’s conduct was a substantial factor and a “but for”
    cause of the plaintiffs’ injuries, citing Texarkana Memorial Hosp.,
    Inc. v. Murdock, 
    946 S.W.2d 836
     (Tex. 1997) and Gutierrez v. Excel
    Corp., 
    106 F.3d 683
    , 687 (5th Cir. 1997).
    This court has stated the standard of review for jury charge
    challenges:
    First, the challenges must demonstrate that the charge as
    a whole creates substantial and ineradicable doubt
    whether the jury has been properly guided in its
    deliberations.   Second, even if the jury instructions
    were erroneous, we will not reverse if we determine,
    based upon the entire record, that the challenged
    instruction could not have affected the outcome of the
    case. If the party wishes to complain on appeal of the
    district court’s refusal to give a proffered instruction,
    that party must show as a threshold matter that the
    proposed instruction correctly stated the law.
    Flores   v.   Cameron    County,    Tex.,     
    92 F.3d 258
    ,    262   (5th   Cir.
    1996)(internal quotation marks omitted).
    Euclid complains that the jury charge did not adequately
    inform the jury that because the injuries claimed by the plaintiffs
    do not arise from any discrete event, the plaintiffs bear the
    burden of showing that the defect or negligence actually caused the
    injuries.     We are not convinced that the charge as a whole, which
    employed language identical to the definitions provided in the
    Texas Pattern Jury Charges, creates substantial and ineradicable
    doubt    whether   the    jury     has    been     properly      guided   in   its
    deliberations.     We therefore will not disturb the verdict based on
    31
    Euclid’s challenge to the jury instructions on causation.
    b. Rucker’s challenge to the jury charge
    Rucker contends on cross-appeal that the district court abused
    its discretion by refusing to grant his request that the jury be
    instructed on the effect of its answers regarding proportional
    responsibility. Unlike Texas state courts, federal courts are free
    to tell juries the effect of their answers.        See Martin v. Texaco,
    Inc., 
    726 F.2d 207
    , 216 (5th Cir. 1985).         The decision whether to
    instruct the jury on the effects of its answers is “a matter of
    discretion for the trial court.”       Martin v. Texaco, Inc., 
    726 F.2d 207
    , 216 (5th Cir. 1984).
    Rucker further complains that the trial court refused his
    requested special instruction that “a plaintiff’s negligence, if
    any, in merely failing to discover a product defect or guard
    against the possibility of its existence cannot form the basis of
    an   affirmative   finding   against    a   plaintiff   on   the   issue   of
    negligence.”   Rucker takes the position that the omission of these
    two instructions led to an incomplete and erroneous charge on
    Euclid’s proportionate responsibility defense and affected the
    outcome of Rucker’s case.      Rucker alleges that, taken together,
    these two jury charge decisions by the district court amounted to
    error in the jury instructions that prejudiced the outcome of the
    case.   See Aero Int’l, Inc. v. United States Fire Ins. Co., 
    713 F.2d 1106
    , 1113 (5th Cir. 1983).
    32
    In Perricone v. Kansas City Southern Rwy. Co., 
    704 F.2d 1376
    (5th Cir. 1983), the district court gave a supplemental instruction
    which informed the jury that the Plaintiff would not recover any
    damages if the Plaintiff was found to be more than 50% negligent.
    This Court affirmed the giving of the supplemental instruction in
    the absence of contemporaneous objection.      
    Id. at 1377
    .     However,
    Perricone does not mandate the giving of such instructions.            We
    find that the failure of the district court to instruct the jury on
    the effect of its answers concerning the Plaintiffs’ proportionate
    responsibility in this case does not call into question the jury’s
    factual determination that Plaintiffs were negligence and that
    their negligence was a producing cause of their injuries.
    In a strict liability cause of action, a plaintiff’s failure
    to discover or guard against a product’s defect is not a defense to
    a defendant’s liability. See Keen v. Ashot Ashkelon, 
    748 S.W.2d 91
    (Tex. 1988).    Therefore, Rucker’s requested charge was a correct
    statement of the law in that regard.   However, we are not left with
    substantial or eradicable doubt that the jury was properly guided
    in its deliberations.   See Flores, 
    92 F.3d at 262
    .     Both Plaintiffs
    and Euclid developed through evidence and argument before the jury
    their theories    concerning   proportionate   responsibility    of   the
    Plaintiffs.    We will not reverse the verdict because, based on the
    entire record, we do not conclude that the requested instructions
    would have affected the outcome of the case.      
    Id.
    33
    VIII. CONCLUSION
    Based   on   the   foregoing,   we   affirm   the   district   court’s
    judgment.
    AFFIRMED.
    34
    DeMOSS, Circuit Judge, dissenting:
    I respectfully dissent.      The plaintiffs in this case did not
    produce evidence that sufficiently demonstrates a causative link
    between    their   alleged   injuries    and    Euclid’s   short-nose   coal
    haulers.   The district court abused its discretion by lowering the
    Daubert standard for admitting expert opinion testimony which was
    neither relevant nor reliable. Finally, this case should have been
    dismissed as time-barred because the plaintiffs’ claims of injury,
    based on one doctor’s subjective evaluation of MRIs, are not
    objectively verifiable as required under Texas case law governing
    the tolling of the statute of limitations pursuant to the discovery
    rule.
    I.
    Euclid, Inc., designs and manufactures 120-ton coal-hauling
    vehicles used at open pit coal mines.          Before the mid-1970s, Euclid
    used a “long-nose” design.      Like a pick-up truck, this design put
    the engine at the front, with the cab above and behind.                 Then,
    responding to consumer demands for greater driver visibility and
    maneuverability, Euclid and its competitors switched to “short-
    nose” designs.     The new designs placed the driver in front, with
    the engine below and behind.      This gives the front of the vehicle
    35
    a flat, snub-nosed appearance.               Euclid’s design changes included
    other modifications, including a shorter wheel base, a trailing arm
    suspension, and rubber struts instead of steel springs.
    When the short-nosed design was introduced in the mid-1970s,
    Euclid sold several vehicles to Texas Utilities Mining Company
    (TUMCO).   The five original plaintiffs in this case, males ranging
    in age from 32 to 46, are former TUMCO employees.                           They all
    operated the Euclid 322 NDT short-nose coal hauler.                  In addition,
    the plaintiffs also operated other heavy machinery in the coal pit,
    including bulldozers, scrapers, water trucks, and end-dump trucks.
    The plaintiffs allege that they have suffered back injuries
    which resulted from “repetitious trauma and severe vibrations”
    experienced while operating the Euclid short-nose coal hauler.
    They sued Euclid, claiming that their back conditions were due to
    the   Euclid    short-nose      coal   hauler’s     defective       design,    which
    rendered the product unreasonably dangerous (the strict products
    liability claim), and Euclid’s negligent design, marketing, and
    failure    to   warn   customers       and    operators     about    safety    risks
    pertaining to the short-nose coal hauler (negligence and gross
    negligence claims).       Their suit was filed in the Eastern District
    of Texas, Marshall Division.
    The sufficiency and admissibility of the testimony offered by
    the   plaintiffs’      expert    witnesses      lies   at    the    heart     of   the
    controversy in this appeal.              The plaintiffs’ five testifying
    -36-
    36
    experts have been divided by the panel majority into two categories
    -- two engineer “liability” experts who testified about the short-
    nose   coal       hauler   and   three   medical     “causation”      experts   who
    testified about the plaintiffs’ injuries.                  Euclid sought summary
    judgment based on its contention that the plaintiffs’ proposed
    expert testimony, necessary to establish causation and liability,
    could not be admitted pursuant to Fed. R. Evid. 702 and Daubert v.
    Merrell Dow Pharmaceuticals, Inc., 
    509 U.S. 579
    , 
    113 S. Ct. 2786
    (1993).    Euclid’s Daubert argument was rejected by the district
    court, but a continuing objection to identified expert testimony
    was permitted.        Euclid also raised a limitations defense, but the
    district court determined that the discovery rule would apply.
    Ultimately, a jury rendered a $2.8 million verdict against
    Euclid.    Euclid moved for judgment as a matter of law (JMOL) on the
    question of liability, all plaintiffs sought JMOL on Euclid’s
    contributory negligence arguments, and plaintiff Tim Rucker, who
    received      a     take-nothing     judgment        because    of    the   jury’s
    determination that he was 70% contributorily negligent, moved for
    a new trial.        These post-trial motions were denied.             All parties
    timely appealed.
    II.
    A detailed discussion of the expert testimony offered at trial
    by   the   plaintiffs       is   necessary      to   the    ensuing   substantive
    -37-
    37
    discussions.     As previously mentioned, the experts fall into two
    general categories -- engineers who testified about the design and
    quality    of   ride    of   the    short-nose    coal   hauler   (“liability
    experts”), and doctors who testified about the plaintiffs’ physical
    condition (“causation experts”).
    A.
    The liability experts testified about Euclid’s coal haulers.
    Mr. Geoff McDonald is an Australian engineer who had experience
    with the    Euclid     short-nose    coal    hauler   dating   back   to   1977.
    Workers asked to operate a problematic Euclid short-nose coal
    hauler at the Blackwater Mine in Australia refused to operate it
    because its ride was so rough.12 Mr. McDonald was asked to test the
    short-nose coal hauler at that time, and based on his testing in
    Australia, he testified that the long-nose haulers are safer
    because they are four to five times less likely to cause injury
    than the short-nose haulers.
    Mr. Arthur Chaseling is a consulting mechanical engineer who
    also testified that he thought the long-nose design was safer.               In
    1996, Mr. Chaseling traveled with Mr. McDonald to Texas to test
    TUMCO’s short-nose coal haulers.            Mr. McDonald testified that the
    12
    Euclid vigorously contests the probity of conclusions based on
    testing of a single hauler in Australia almost 20 years ago.
    Euclid contends that the haulers sent to Australia were specially
    modified to the customer’s specifications. The company has also
    conceded that the hauler sent to Australia may have been a lemon.
    -38-
    38
    mine operations and physical layout were similar to those at the
    Blackwater mine.   Messrs. Chaseling and McDonald together measured
    the vibrations experienced by TUMCO’s employees who operated the
    Euclid short-nose coal hauler.           These tests were conducted by
    attaching an accelerometer to the metal frame below the seat of a
    Euclid coal hauler.       Using these measurements, Mr. Chaseling
    determined that the Euclid short-nose coal hauler’s vibrations
    exceed the health and safety limits of the International Standards
    Organization (ISO).13    Messrs. Chaseling and McDonald did not test
    any of the other earth-moving equipment operated at the mine to
    measure their vibrations, and they did not attempt any sort of
    comparison   between    the   short-nose   coal   hauler   and   the   other
    machines operated by the plaintiffs.
    B.
    The key causation expert was Dr. Charles N. Aprill, a medical
    doctor specializing in diagnostic radiology.        He performed MRIs on
    the backs of approximately ninety TUMCO employees, including the
    plaintiffs, who operated the Euclid short-nose coal hauler.            These
    employees also operated other heavy machinery such as scrapers,
    bulldozers, water trucks, and end-dump trucks,14 but Dr. Aprill’s
    13
    The ISO standards are not binding on Euclid, and Euclid
    contests the probity of using these standards.
    14
    Plaintiff Johnny W. Bartley testified:
    [T]here were several jobs that a hauler operator would
    -39-
    39
    tests did not indicate that he had considered the effect of, or
    differentiated among the TUMCO employees based on, their length of
    employment or the amount of time they spent operating particular
    machines.   He compared the results of these MRIs with a “control
    group” of MRIs performed on a group of “consecutive patients who
    were scanned roughly during the time these [TUMCO] patients were
    scanned, who were referred because they had some sort of back
    problem.”   The control group patients were selected to be age- and
    gender-matched to the test group of ninety TUMCO employees, but the
    control group did not include anyone who operated coal haulers or
    any other kind of earth-moving equipment.
    Dr. Aprill found “endplate infractions” -- impact craters
    which form in an intervertebral disc when a load is applied to it
    -- in 90% of the TUMCO employees and in 68% of the “control group”
    of other back pain patients being treated by Dr. Aprill.   He also
    found that while the endplate infractions occurring in the general
    perform in hauler operator classification, of course, one
    being operate the hauler, another being to run the crusher,
    run the water truck and assorted pump duties, the
    dewatering type job whereupon rains you would pump water
    out of the pit to help dry it up. You were kind of a do-
    all individual.
    All the other plaintiffs except Mike R. Rucker testified that they
    operated the same machines described by Mr. Bartley, as well as a
    bulldozer. Mr. Rucker had only begun driving the coal hauler for
    TUMCO in late 1990 or early 1991, and he testified that in addition
    to the coal hauler he also operated the water truck, end-dump
    truck, and a backhoe. During previous employment, Mr. Rucker had
    been a manual laborer, had operated other heavy machinery, such as
    a forklift, and had injured his back on the job.
    -40-
    40
    back-pain population clustered between the lower dorsal spine and
    the upper lumbar spine, the TUMCO employees exhibited endplate
    infractions in that area as well as throughout the lumbar spine.
    According to Dr. Aprill, these endplate infractions render one more
    susceptible     to   back   injury.     Dr.     Aprill    concluded     that   the
    “repeated vertical compression” experienced by the TUMCO employees
    caused the endplate infractions.
    On cross-examination, Dr. Aprill opined that for “the normal
    population without any occupational stresses,” the incidence of
    endplate infractions is “something in the order of forty percent or
    so,”    and   that   “any    person    that’s        subjected   to    repetitive
    compression, whatever the source, is likely to develop changes
    similar to what we saw.”          Dr. Aprill stated that he had not
    compared the MRIs of the backs of short-nose coal hauler operators
    to test results for the operators of any other type of coal hauler;
    neither   had   he   compared   the    MRIs     of    short-nose      coal   hauler
    operators to those of workers who operated bulldozers, end-dump
    trucks, scrapers, water trucks, or tractors.                He further stated
    that he could not testify about the effect of operating those kinds
    of heavy equipment because he had “not seen MRI scans on large
    numbers of other heavy equipment operators.” When challenged about
    his conclusions that the plaintiffs’ endplate infractions were
    caused by the vibrations of the Euclid short-nose coal hauler, Dr.
    Aprill conceded that he could not point to any study which might
    indicate how much vibration was necessary to produce the injuries
    -41-
    41
    he identified.    His method and findings had not been reviewed by a
    statistician or an epidemiologist or submitted for peer review and
    publication, and no rate of error had been calculated for his
    theory.   Furthermore, he had not conducted any prior research or
    studies -- nor had he submitted any papers or published any
    articles -- on vibration and its effects on the back.
    Dr. Richard W. Bunch is a ergonomics consultant and physical
    therapist who rode in a Euclid short-nose coal hauler.    Dr. Bunch
    used a pen and a pad of paper to keep track of the jerks and jolts
    that he felt during the ride.    Based on his conclusions from this
    “semi-objective” field experiment, he testified that the vibrations
    experienced by the plaintiffs when they operated the Euclid short-
    nose coal hauler contributed to their injuries and that the design
    of the cab was not sufficient to protect the operator from the
    vibrations.   Dr. Bunch’s test was not subjected to peer review.
    Dr. Kelvin A. Samaratunga is a neurosurgeon and a clinician
    who evaluates and treats back pain.        He reviewed all of the
    previously described expert testimony, and he rode on a Euclid
    short-nose coal hauler. In particular, he reviewed the plaintiffs’
    medical records and MRIs.     He testified that he agreed with Dr.
    Aprill that the endplate infractions were the result of whole body
    vibration, and that they would eventually lead to back problems for
    the plaintiffs.     On cross-examination, Dr. Samaratunga conceded
    that he was not an expert on vibration and he had not performed any
    studies or published any materials in that field of study.    He is
    -42-
    42
    not an epidemiologist or a statistician either.     When asked, Dr.
    Samaratunga indicated that he could not identify any published
    study which indicated that the levels of vibration measured in the
    short-nose coal haulers could cause the injuries of which the
    plaintiffs complained.   The materials reviewed by Dr. Samaratunga
    did not address the effect, if any, of the other equipment operated
    in the mines by the plaintiffs.
    III.
    Euclid unsuccessfully moved for judgment as a matter of law
    based on the insufficiency of the evidence to establish a causative
    link between the plaintiffs’ injuries and their operation of the
    Euclid short-nose coal hauler.         De novo review applies, with
    inferences drawn in favor of the nonmoving party.   See Gutierrez v.
    Excel Corp., 
    106 F.3d 683
    , 686 (5th Cir. 1997).
    A.
    Texas law provides the substantive rule of what the plaintiffs
    were required to establish in order to prove Euclid’s liability.
    The landmark decision of Erie Railroad Co. v. Tompkins, 
    304 U.S. 64
    , 
    58 S. Ct. 817
     (1938), established that “[e]xcept in matters
    governed by the Federal Constitution or by Acts of Congress, the
    law to be applied in any case is the law of the State.”    
    304 U.S. at 78
    , 
    58 S. Ct. at 822
    .      Generally speaking, federal courts
    -43-
    43
    sitting in   diversity   apply   the   substantive   law   of    the   state
    providing the law of decision, while following federal procedural
    law. See, e.g., Gasperini v. Center for Humanities, Inc., 
    518 U.S. 415
    , 
    116 S. Ct. 2211
    , 2219 (1996).        When the difference between
    applying state law and federal law is outcome-determinative, that
    factor is a strong indicator that the federal court should apply
    state law.   See 
    id. at 426-28
    , 
    116 S. Ct. at 2219-20
    ; Guaranty
    Trust Co. v. York, 
    326 U.S. 99
    , 
    65 S. Ct. 1464
     (1945).          The test of
    outcome determination cannot, however, be applied mechanically; a
    federal court must instead be guided by “the twin aims of the Erie
    rule: discouragement of forum-shopping and avoidance of inequitable
    administration of the laws.”     Gasperini, 
    518 U.S. at 428
    , 
    116 S. Ct. at 2220
     (quoting Hanna v. Plummer, 
    380 U.S. 460
    , 468, 
    85 S. Ct. 1136
    , 1142 (1965)).
    Consistent with these principles, it is well established that
    in diversity cases, state law determines the quality and quantum of
    evidence that must be produced to establish a cause of action,
    while the standard for reviewing the sufficiency of evidence to
    sustain a jury verdict on appeal is indisputably governed by a
    federal standard.     See, e.g., Jones v. Wal-Mart Stores, Inc., 
    870 F.2d 982
    , 986 (5th Cir. 1989); Tutor v. Ranger Ins. Co., 
    804 F.2d 1395
    , 1398 (5th Cir. 1986); Ayers v. Sears, Roebuck & Co., 
    789 F.2d 1173
    , 1175 (5th Cir. 1986); McCandless v. Beech Aircraft Corp., 
    779 F.2d 220
    , 223 (5th Cir. 1985); Fairley v. American Hoist & Derrick
    -44-
    44
    Co., 
    640 F.2d 679
    , 681 (5th Cir. Unit A 1981).            Federal law thus
    mandates that we review the jury’s verdict by the same standard as
    the   district   court,   affirming     unless   “there    is   no     legally
    sufficient evidentiary basis for a reasonable jury to find” as the
    jury did.   Fed. R. Civ. P. 50(a)(1); see Denton v. Morgan, 
    136 F.3d 1038
    , 1044 (5th Cir. 1998).    The Erie doctrine, however, mandates
    that the object of this inquiry be whether the evidence adduced by
    the plaintiffs adequately establishes a prima facie case according
    to the laws of the state of Texas, such that the jury verdict may
    be approved.
    This result is necessary both to discourage forum-shopping and
    to ensure the equitable administration of the laws.             Were we to
    apply some lower standard -- essentially lowering the burden of
    proof -- products liability and negligence plaintiffs would have a
    considerable incentive to file suit in federal court rather than in
    state court because it would be easier for them to win a case.
    That is precisely what the Erie doctrine seeks to prevent.             In this
    case, we must therefore consider whether the plaintiffs have
    proved, as a matter of Texas law, that their injuries were caused
    by the Euclid short-nose coal hauler.
    B.
    Under Texas law, causation in fact is an element of the both
    the   plaintiffs’   strict   products     liability   claims     and    their
    -45-
    45
    negligence claims.      See, e.g., Union Pump Co. v. Allbritton, 
    898 S.W.2d 773
    , 775 (Tex. 1995).15       In order to establish this element,
    common to all their various claims that Euclid engaged in tortious
    activity, the plaintiffs must prove that vibrations produced by the
    short-nose    coal   hauler   constituted     “a   substantial      factor   in
    bringing about the injury and without which no harm would have
    occurred.”   E.g., Havner v. E-Z Mart Stores, Inc., 
    825 S.W.2d 456
    ,
    458-59 (Tex. 1992) (emphasis supplied); Nixon v. Mr. Property
    Management    Co.,    
    690 S.W.2d 546
    ,    549   (Tex.   1985)    (emphasis
    supplied);    see    also   Restatement     (Third)   of   Torts:    Products
    Liability § 15 (1997) (hereinafter Restatement (Third)) (“Whether
    a product defect caused harm to persons or property is determined
    by the prevailing rules and principles governing causation in
    15
    As the Texas Supreme Court neatly summarized:
    Negligence requires a showing of proximate cause, while
    producing cause is the test in strict liability. Proximate
    and producing cause differ in that foreseeability is an
    element of proximate cause, but not of producing cause.
    Proximate cause consists of both cause in fact and
    foreseeability. Cause in fact means that the defendant’s
    act or omission was a substantial factor in bringing about
    the injury which would not otherwise have occurred.       A
    producing cause is “an efficient, exciting, or contributing
    cause, which in a natural sequence, produced injuries or
    damages complained of, if any.” Common to both proximate
    and producing cause is causation in fact, including the
    requirement that the defendant’s conduct or product be a
    substantial factor in bringing about the plaintiff’s
    injuries.
    Union Pump Co., 
    898 S.W.2d 773
    , 775 (Tex. 1995) (emphasis supplied,
    citations omitted).
    -46-
    46
    tort.”).    By requiring that the allegedly tortious activity be a
    factor “without which no harm would have occurred,” the test
    embodies, as one of its elements, the “traditional ‘but-for’ rule
    of causation.”       1 J. Hadley Edgar, Jr. & James B. Sales, Texas
    Torts and Remedies § 1.05[2][a], at 1-111 (1998); see also W. Page
    Keeton et al., Prosser and Keeton on Torts § 41, at 266 (5th ed.
    1984) (hereinafter, Prosser & Keeton) (“Restricted to the question
    of causation alone, and regarded merely as a rule of exclusion, the
    ‘but-for’     rule   serves   to   explain   the   greatest   number   of
    cases . . . .”); David W. Robertson, The Common Sense of Cause in
    Fact, 75 Texas L. Rev. 1765, 1768 (1997) (noting that the but-for
    standard is the “most widely accepted test” for determining cause
    in fact); Restatement (Third), supra, § 15.        That being the case,
    Texas law requires that the plaintiffs prove but-for causation with
    respect to the alleged injurious effect of the short-nose coal
    hauler; it is not sufficient for the plaintiffs to merely present
    evidence that the vibrations produced by the short-nose coal hauler
    constituted a “substantial factor” in producing the plaintiffs’
    injuries.16
    16
    Strictly speaking, the “substantial factor” inquiry is
    probative only in the event that “two causes concur to bring about
    an event, and either one of them operating alone, would have been
    sufficient to cause the identical result.”       Prosser & Keeton,
    supra, § 41, at 266.     The plaintiffs have not argued that the
    Euclid short-nose coal hauler is one of several factors which would
    have independently caused their injuries, so we need not consider
    whether these facts fall into that special subset of cases.
    -47-
    47
    C.
    A five-step logical process provides a careful (if tedious)
    model for determining whether a given event is a cause in fact of
    a plaintiff’s injuries.       In summary, the five logical steps for
    proving but-for causation are as follows:
    (a) identify the injuries in suit; (b) identify the
    wrongful conduct; (c) mentally correct the wrongful
    conduct to the extent necessary to make it lawful,
    leaving everything else the same; (d) ask whether
    the injuries would still have occurred had the
    defendant been acting correctly in that sense; and
    (e) answer the question.
    Robertson, supra, at 1771.      The application of this framework of
    analysis will help to locate any logical flaw which may taint the
    plaintiffs’ theory of causation.
    The first step is to identify the plaintiffs’ injuries.              In
    this case, the plaintiffs have alleged that they have suffered
    endplate   infractions   in   their    spines   which   render   them   more
    susceptible to serious back pain in the future.         The second step is
    to name the defendant’s allegedly wrongful conduct.         Because there
    are multiple answers at this second step relating to each of the
    plaintiffs’ theories of liability, we must consider each theory
    separately.
    -48-
    48
    1.
    The plaintiffs have a strict products liability claim and a
    negligence claim based on defective design. The allegedly wrongful
    conduct for the purposes of both of these claims was negligent
    design of the short-nose coal hauler pursuant to Euclid’s business
    decisions to stop manufacturing long-nose coal haulers and to begin
    manufacturing short-nose coal haulers.       Because these separate
    claims focus on the same activity, they may be grouped for the
    purpose of determining whether that activity was a cause in fact of
    the plaintiffs’ injuries.
    Taking the third analytical step with respect to these claims,
    we must hypothesize a scenario that would erase the effect of the
    allegedly wrongful conduct. According to the plaintiffs’ theory of
    their products liability case, the short-nose coal hauler subjects
    its operator to harmful vibration, rendering the machine defective
    and unreasonably dangerous.17   Similarly, in the negligence rather
    17
    “In Texas, section 402A of the Restatement (Second) of Torts
    governs claims for strict liability in tort.” American Tobacco Co.
    v. Grinnell, 
    951 S.W.2d 420
    , 426 (Tex. 1997) (citing Firestone
    Steel Prods. Co. v. Barajas, 
    927 S.W.2d 608
    , 613 (Tex. 1996);
    McKisson v. Sales Affiliates, Inc., 
    416 S.W.2d 787
    , 788-89 (Tex.
    1967)). According to that rule:
    (1) one who sells any product in a defective condition
    unreasonably dangerous to the user or consumer or to his
    property is subject to liability for physical harm thereby
    caused to the ultimate user or consumer, or to his
    property, if
    (a) the seller is engaged in the business of selling such
    a product, and
    -49-
    49
    than strict liability context, the plaintiffs additionally contend
    that the Euclid acted negligently in designing the short-nose
    hauler, such that the machine’s operators were subjected to harmful
    vibrations, thus resulting in injury.           In order to overcome the
    argument that the balance between “the utility of the product and
    the   risk   involved   in   its   use”    precludes   liability   on   these
    theories, see, e.g., American Tobacco Co. v. Grinnell, 
    951 S.W.2d 420
    , 432 (Tex. 1997), the plaintiffs pointed to the older long-nose
    coal hauler as a safer alternative design which, they contend, did
    not suffer from the same defect.
    For the purpose of these design-based theories, then, the
    third step of the analysis would be accomplished by trading the
    short-nose coal haulers for Euclid’s older long-nose coal hauler
    models. The inquiry would then be completed by determining, at the
    fourth step, whether the plaintiffs’ injuries would have occurred
    if they drove long-nose coal haulers and not short-nose coal
    haulers. If not, taking the fifth and final logical step, cause in
    fact has been established.
    (b) it is expected to and does reach the user or consumer
    without substantial change in the condition in which it is
    sold.
    Restatement (Second) of Torts § 402A (1965). “A product may be
    unreasonably dangerous because of a defect in marketing, design, or
    manufacturing.” Grinnell, 951 S.W.2d at 426.
    -50-
    50
    2.
    Regarding     the     plaintiffs’    remaining         negligence    and   gross
    negligence claims, the allegedly wrongful conduct was a marketing
    defect, namely, Euclid’s failure to warn customers and operators
    about safety risks arising from vibration in the short-nose coal
    hauler.    The plaintiffs contend that such warnings would have
    allowed them to minimize their exposure to vibration and repetitive
    trauma while operating the short-nose coal hauler.
    Removing the effect of the wrongful conduct to take the third
    logical   step    in   this    scenario,      one    must    hypothesize    a     work
    environment in which TUMCO and its employees were warned about
    safety risks arising from the short-nose coal hauler’s tendency to
    vibrate. One would therefore assume that precautions were taken to
    reduce or eliminate the exposure to vibration, either by TUMCO’s
    refusal to buy Euclid’s short-nose coal hauler, the plaintiffs’
    refusal   to     operate      the   machine,    or    perhaps      some    sort    of
    prophylactic precaution such as a modification of the machine
    itself or of the employees’ usage of the machine.                        Given this
    scenario, the fourth step leads to the question of whether the
    plaintiffs would have been injured in a work environment exactly
    the same as it actually was except that they were not exposed to
    unsafe vibrations in the short-nose coal hauler.                    If it can be
    proved that there would have been no injury in this scenario, cause
    -51-
    51
    in fact will have been established for the plaintiffs’ negligence
    claim against Euclid.
    3.
    Based on the above reasoning, the key logical step in both
    scenarios    is   the   fourth    step     designated     above,    specifically,
    “whether the injuries that the plaintiff[s] suffered would probably
    still have occurred had the defendant behaved correctly in the
    sense indicated.”       Robertson, supra, at 1771.             It is apparent that
    in order to establish Euclid’s liability on theories of strict
    products liability or negligence, the plaintiffs were required to
    present   evidence      to   prove   one      of   the   two   factual   causation
    scenarios.    They could show either that similarly situated workers
    who operated long-nose coal haulers but not short-nose coal haulers
    would not experience the injuries experienced by the plaintiffs
    (products liability and design defect claims), or that similarly
    situated workers who operated all the machines operated by the
    plaintiffs except the short-nose coal hauler would not experience
    the injuries experienced by the plaintiffs (marketing defect or
    failure-to-warn claims).         I now turn to those absolutely necessary
    links of causation.
    -52-
    52
    D.
    -53-
    53
    Our guiding star in considering whether the plaintiffs have
    adequately established causation to justify imposing liability upon
    Euclid should be the recent treatment of tort causation by the
    Supreme Court of Texas in Merrell Dow Pharmaceuticals, Inc. v.
    Havner, 
    953 S.W.2d 706
     (Tex. 1997) (hereinafter, Havner).
    In that case the court reversed a jury verdict in favor of
    plaintiffs who had claimed that use of the drug Bendectin caused a
    birth defect in their child.         The central issue throughout the
    litigation was the reliability of the expert testimony offered to
    establish causation.       Though the specific issue before the court
    was whether the Havners’ evidence was scientifically reliable and
    constituted “some evidence” to support the plaintiffs’ judgment,
    the circumstances of the case led the court to consider precisely
    what a plaintiff must establish to raise a fact issue of whether a
    drug   caused   an   individual’s   birth    defect.       This   prompted   a
    discussion of some very fundamental issues relating to proving
    causation.
    The court noted that causation in toxic tort cases can be
    discussed in terms of either general or specific causation:
    General causation is whether a substance is capable
    of causing a particular injury or condition in the
    general population, while specific causation is
    whether     a     substance      caused     a    particular
    individual’s injury.          In some cases, controlled
    -54-
    54
    scientific           experiments       can     be    carried    out    to
    determine if a substance is capable of causing a
    particular injury or condition, and there will be
    objective criteria by which it can be determined
    with     reasonable        certainty           that    a     particular
    individual’s injury was caused by exposure to a
    given substance.
    Havner, 953 S.W.2d at 714-15.            In many toxic tort cases, however,
    direct experimentation cannot be done.                     As a result, there can be
    no reliable, direct evidence of specific causation. The court thus
    reasoned:
    In     the     absence     of    direct,       scientifically
    reliable proof of causation, claimants may attempt
    to demonstrate that exposure to the substance at
    issue        increases     the     risk      of     their    particular
    injury.       The finder of fact is asked to infer that
    because the risk is demonstrably greater in the
    general        population        due      to      exposure     to     the
    substance, the claimant’s injury was more likely
    than not caused by that substance.                     Such a theory
    concedes that science cannot tell us what caused a
    particular plaintiff’s injury.                    It is based instead
    on a policy determination that when the incidence
    -55-
    55
    of a disease or injury is sufficiently elevated due
    to exposure to a substance, someone who was exposed
    to   that   substance   and    exhibits     the   disease   or
    injury can raise a fact question on causation.
    Id. at 715 (emphasis supplied) (citing Daubert v. Merrell Dow
    Pharms., Inc., 
    43 F.3d 1311
    , 1320 n.13 (9th Cir. 1995) (on remand
    from the Supreme Court)).
    While Havner dealt with causation principles in the context of
    a toxic tort case, the underlying issues are compellingly similar
    to the problems of proving that the Euclid short-nose coal hauler
    caused   the    plaintiffs’   injuries     in   this   case.     First,     the
    plaintiffs in Havner, just like the plaintiffs in the instant case,
    brought a products liability suit based on theories of negligence,
    defective design, and defective marketing. Second, the Havners did
    not contend that all limb reduction birth defects are caused by
    Bendectin, and, likewise, the plaintiffs before us in this appeal
    recognize that not all endplate infractions are caused by driving
    Euclid’s short-nose coal hauler.         Finally, in Havner, as here, the
    only proof of causation offered by the plaintiffs was scientific
    expert testimony relating the results of studies on the association
    between the use of a product and certain injuries which allegedly
    resulted from that use.
    -56-
    56
    The plaintiffs and the panel majority would prefer that this
    case be treated differently than Havner, asserting that the present
    litigation is nothing like the infamous Bendectin cases.              Quite to
    the    contrary,     this   case    bears      many   similarities    to    that
    significant, trend-setting series of cases.            An underlying premise
    in many toxic tort cases is that the plaintiff has suffered an
    injury, such as cancer, which may have occurred even if the
    plaintiff had not been exposed to the substance at issue.                  So too
    in this case, the plaintiffs claim that they have suffered an
    injury, endplate infractions, which may have occurred even if they
    had never operated the short-nose hauler.              Furthermore, and very
    significantly, just as toxic tort causation (as a practical matter)
    usually cannot be established by exposing human subjects to the
    substance in question for testing purposes, direct experimentation
    cannot be done (or at least has not been done) to prove objectively
    that use of the short-nose coal hauler causes endplate infractions,
    and these plaintiffs are therefore left to attempt to prove their
    case    using      epidemiological      (or,     in    this   case,    pseudo-
    epidemiological) studies.          In these respects, the case sub judice
    is much more akin to a toxic tort case than a traditional personal
    injury case, and as such, we should not shy away from considering
    Texas law regarding toxic torts.
    Because causation cannot be proved directly by the plaintiffs,
    the only remaining avenue available in tort law for the purpose of
    -57-
    57
    proving causation is to demonstrate that their use of the short-
    nose coal hauler increased their risk of injury.       In order to
    determine causation in these circumstances, the finder of fact must
    be guided by the “more likely than not” burden of proof.
    Havner established as a matter of Texas law that the more
    likely than not burden of proof requires, in order to be probative
    of causation, that epidemiological studies must demonstrate more
    than a doubling of the risk of injury.18        The supreme court
    explained:
    Although we recognize that there is not a
    precise fit between science and legal burdens of
    proof, we are persuaded that properly designed and
    executed epidemiological studies may be part of the
    evidence supporting causation in a toxic tort case
    and that there is a rational basis for relating the
    requirement that there be more than a “doubling of
    the risk” . . . to the more likely than not burden
    of proof.
    18
    Of course, Havner does not purport to require that, and we
    need not consider whether, epidemiological standards must be used
    be used to indirectly prove tort causation with scientific medical
    opinion testimony. It is certainly worthy of note, however, that
    this Court has previously stated: “While we do not hold that
    epidemiologic proof is a necessary element in all toxic tort cases,
    it is certainly a very important element.” Brock v. Merrell Dow
    Pharms., Inc., 
    874 F.2d 307
    , 313 (5th Cir. 1989).
    -58-
    58
    Havner, 953 S.W.2d at 717. This same standard of causation applies
    to the scientific evidence adduced by the plaintiffs in this case.
    Even though the studies conducted by the plaintiffs’ experts are
    not “epidemiological studies,” the plaintiffs’ studies seek to
    accomplish the same objective as an epidemiological study -- they
    attempt to explain the cause of the endplate infractions which
    their MRI studies show that the plaintiffs experienced.          Indeed,
    the only reason why the plaintiffs’ experts’ studies are not
    epidemiological   studies    is   because   they   were   not   conducted
    according to well-established standards for reliably conducting
    epidemiological inquiries.
    A scientific study providing indirect scientific evidence of
    tort causation, standing alone, is not sufficiently probative of
    legal causation if it does not tend to show that the suspected
    cause is more likely than not the actual cause of an injury.          In
    other words, such a study is not probative of causation if it fails
    to demonstrate that the suspected cause doubles the risk of injury
    as compared to the general population which was not exposed or
    subjected to the suspected cause.
    -59-
    59
    E.
    -60-
    60
    Assuming,   arguendo,   the   admissibility   of   the   plaintiffs’
    experts’ testimony,19 the evidence of causation is insufficient to
    support a verdict of negligence or strict liability.            The key flaw
    in the plaintiffs’ evidence is that it fails to show that the
    plaintiffs’ common injuries and exposure to the Euclid short-nose
    coal hauler are anything more than a coincidence.
    Dr. Aprill’s “study” revealed endplate infractions in 90% of
    the TUMCO employees and 68% of the “control group” of back pain
    patients.    Based on this statistical comparison, it is apparent
    that any given back-pain patient most likely would have had the
    infractions even though he had not operated a Euclid short-nose
    hauler.20    Likewise, it is apparent that the risk of endplate
    19
    For reasons explained later, the expert opinions were not
    admissible. See infra Part IV.
    20
    The panel majority refers to Minnesota Mining & Manufacturing
    Co. v. Atterbury, No. 06-97-00099-CV (Tex. App.--Texarkana July 31,
    1998, n.p.h.) (not designated for publication), 
    1998 WL 436916
    (hereinafter, 3M), for the propositions that there is “no
    requirement that a party must have reliable epidemiological
    evidence of a relative risk of 2.0 or greater” and that “[r]eliable
    evidence of relative risk less than 2.0 can be considered, but must
    be supported by other credible, reliable evidence of causation.”
    Majority Op. at Part IV(c) (citing 3M, 
    1998 WL 436916
    , at *15). It
    is certainly true that the court in Havner did not impose a
    requirement that epidemiological evidence be used to prove
    causation, but that does not mean that epidemiological evidence
    that does not show a doubling of the risk may be used or that such
    evidence will support a jury’s verdict.
    The 3M Court relied on Pick v. American Medical Sys., Inc., 
    958 F. Supp. 1151
     (E.D. La. 1997), for the proposition that
    “epidemiological evidence with a relative risk lower than 2.0
    should be considered because . . . it is relevant evidence.” 3M,
    
    1998 WL 436916
    , at *15. Several things should be noted about the
    -61-
    61
    infractions in the TUMCO employee test group is not more than twice
    the risk of endplate infractions in the control group.               Plainly
    then, the statistics produced by the study do not tend to establish
    the plaintiffs’ case.     Cf. Havner, 953 S.W.2d at 717.
    Moving beyond the statistical findings, however, the majority
    primarily rests its conclusions upon the so-called “fingerprint” of
    injury   characteristics      exposed       by   Dr.   Aprill’s   subjective
    interpretation of the number and physical distribution throughout
    the spine of endplate infractions as exhibited in the plaintiffs’
    MRIs.    Unfortunately, this “fingerprint” evidence is completely
    irrelevant because it bears absolutely no relation whatsoever to
    the links   of    causation   that   the     plaintiffs   are   obligated   to
    demonstrate.     The “fingerprints” give us no guidance as to whether
    Pick opinion. First, Pick is the opinion of a federal district
    court in Louisiana, applying Louisiana law to a products liability
    and negligence case arising from a claim that Mr. Pick’s penile
    implant, designed and manufactured by the defendant, caused Mr.
    Pick to suffer from various health disorders which led to his
    eventual death. Our task in deciding diversity cases is to apply
    state law in the same fashion as we can best discern that the state
    supreme court would apply it.        Although in deciding 3M the
    Texarkana Court of Appeals relied on a decision of the United
    States District Court for the Eastern District of Louisiana, Pick,
    to inform its interpretation of an opinion of the Supreme Court of
    Texas, Havner, I am not persuaded that the Supreme Court of Texas
    would follow the same path.      Second, Pick refers only to the
    admissibility of epidemiological evidence of relative risk above
    1.0, not whether such evidence will support a jury verdict imposing
    liability. See Pick, 
    958 F. Supp. at 1160
    . In fact, the court in
    Pick granted summary judgment for the defendant based on the
    inadequacy of the plaintiffs’ evidence to prove causation, and the
    plaintiffs’   evidence   in   that   case   was  not   limited   to
    epidemiological evidence. See 
    id. at 1173
    .
    -62-
    62
    the injuries would have occurred if the plaintiffs had operated
    long-nose         coal    haulers   rather    than   short-nose    coal   haulers.
    Neither do the “fingerprints” demonstrate that the injuries would
    not have occurred absent exposure to the short-nose coal hauler.
    There is no proof that the level of vibration produced by the
    short-nose coal hauler was in any respect significantly different
    from the level of vibration generated by other heavy earth-moving
    equipment operated by the plaintiffs.21                    In fact, Dr. Aprill
    conceded that he could not distinguish, based on his study, which
    of the many pieces of heavy machinery operated by the coal haulers
    might have been the cause of the endplate infractions.                 That is so,
    at        least   in     part,   because     the   study   made   no   attempt    to
    differentiate among its subjects based on their work histories,
    including what types of equipment the TUMCO employees had operated,
    and for what periods of time they operated that equipment.                       Dr.
    Aprill had no way to eliminate from his study the effects of other
    sources of vibration.
    As explained earlier, see supra Part III(B), one of the above
    mentioned factual scenarios had to be established as a factual
    21
    Experts for Euclid, on the other hand, did test the other
    machines and found that, assuming that the vibration of these
    machines was a concern at all, other machines such as the bulldozer
    and the scraper presented a much greater concern for the operators
    than did the short-nose coal hauler. For the apparent purpose of
    demonstrating to the jury that the vibrations were not a serious
    concern, Euclid’s experts also compared the short-nose coal
    hauler’s vibrations to those generated by a Corvette and a Suburban
    driven around the courthouse square.
    -63-
    63
    predicate to the plaintiffs’ recovery.22           Without a tie to the
    particular injuries experienced by the plaintiffs, the opinions of
    Dr. Bunch and Dr. Samaratunga shift on their foundations.                 In
    essence, these two witnesses confirmed that the Euclid short-nose
    coal hauler vibrates, that vibrations can cause back injury, and
    that the plaintiffs who operated the short-nose coal hauler have
    indeed suffered back injury.      They relied on Dr. Aprill’s analysis
    to connect their knowledge about the machine and theories about
    whole body vibration to the plaintiffs’ flesh and blood.               Their
    testimony does not repair the fatal flaw in Dr. Aprill’s testimony.
    The liability experts’ opinions that the Euclid short-nose
    hauler may     subject   its   operators   to   injury   due   to   prolonged
    exposure to harmful vibrations suffer from the same variety of
    logical flaw -- they are not linked to the specific injury claimed
    by the plaintiffs.       Messrs. Chaseling and McDonald started with
    their measurements of the vibrations produced by the short-nose
    coal hauler.    They then compared these findings to recommendations
    22
    An alternative, more formal logical explanation for the
    problem presented by this case may be that Dr. Aprill’s reasoning
    suffers from the “fallacy of post-hoc statistics,” which occurs
    when “[d]ifferences that are discovered by accident then become the
    verification of an ad-hoc hypothesis that was the result of the
    observation.” Kenneth R. Foster & Peter W. Huber, Judging Science:
    Scientific Knowledge and the Federal Courts 143 (1997) (quoting
    Petr Skrabanek & James McCormick, Follies and Fallacies in Medicine
    (1990)). Dr. Aprill conducted his tests in 1995; Messrs. Chaseling
    and McDonald were summoned to Texas in 1996. It appears that the
    vibration theory was developed to support Dr. Aprill’s analysis of
    the MRIs. “This is fallacious because it confuses pre- and post-
    test probabilities.” Id. (quoting Skrabanek & McCormick, supra).
    -64-
    64
    by the ISO concerning what amount of vibration may be acceptable.
    Having determined that the short-nose coal hauler’s level of
    vibration is unacceptable according to ISO standards, these experts
    then reasonably opined that exposure to too much vibration can be
    harmful.    All of this information is pertinent to the plaintiffs’
    claims,    but   none   of   it   provides   the   answer   to   the   ultimate
    question.    None of it links the particularized information about
    the vibrations experienced by the plaintiffs in this case to the
    types of injuries experienced by the plaintiffs in this case.             None
    of it eliminates other possible sources of vibration as the cause
    of the plaintiffs’ injuries.          Their testimony therefore does not
    permit the inference that the specific injuries claimed by the
    plaintiffs were caused by the Euclid short-nose coal hauler.
    Simply put, nothing in the evidence presented by Dr. Aprill or
    any of the plaintiffs’ other experts suggests the required but-for
    link between the short-nose hauler’s vibrations and the incidence
    of endplate infractions in the plaintiffs’ backs.                Explained yet
    another way, even if Dr. Aprill’s study demonstrates that the
    endplate infractions observed in the plaintiffs’ backs are more
    likely than not attributable to some aspect of their occupation
    (which, as a matter of logic, is all that his studies could
    possibly demonstrate), the study does not link the Euclid short-
    nose hauler to the increased incidence of endplate infractions.
    The study does not distinguish the effects of the Euclid short-nose
    -65-
    65
    coal hauler from the effects of any other kind of equipment
    operated by the plaintiffs.      Moreover, a mere “blend” of expert
    opinions depicting a blurry relation resembling a causative link
    between    Euclid’s   product   and   the    plaintiffs’   injuries   is
    insufficient to support the verdict.23       “Proof of causation cannot
    turn upon speculation or conjecture.”           Leitch v. Hornsby, 
    935 S.W.2d 114
    , 119 (Tex. 1996) (internal quotation marks omitted).
    The plaintiffs showed that they and their coworkers operated
    the Euclid short-nose coal hauler.          The plaintiffs demonstrated
    that the Euclid short-nose coal haulers vibrate, and that may be a
    bad thing.    Finally, the plaintiffs explained that, in the opinion
    of Dr. Aprill, they and their coworkers have endplate infractions
    which appear in their spines in a unique fashion.              But the
    plaintiffs did not establish the crucial logical link -- that it
    was the act of operating the short-nose coal haulers that caused
    their endplate infractions.     That logical lapse should be fatal to
    their case.    Because the plaintiffs have not presented evidence
    that establishes that operating Euclid short-nose coal haulers was
    a cause in fact of the plaintiffs’ endplate infractions, Euclid
    should have been granted JMOL.24
    23
    This is a fair characterization of the testimony given by Dr.
    Samaratunga, who essentially provided an “expert” summarization of
    previously admitted expert testimony, apparently for the purpose of
    bridging the gaps and creating an illusion of logical cohesion.
    24
    The panel majority is absolutely correct in its statement of
    law that if an “act actively aids in producing an injury, it need
    not be the sole cause, but it might be a concurring cause, and such
    -66-
    66
    IV.
    Euclid unsuccessfully sought to suppress the testimony of the
    plaintiffs’ expert witnesses by challenging their qualifications to
    present expert opinion.       Euclid now challenges on appeal the
    admission of plaintiffs’ experts’ testimony.     This Court reviews
    for abuse of discretion.     See General Elec. v. Joiner, 
    118 S. Ct. 512
    , 517 (1997); Moore v. Ashland Chem. Inc., 
    151 F.3d 269
    , 274
    (5th Cir. 1998) (en banc).
    The Federal Rules of Evidence provide:
    Rule 702. Testimony by Experts
    If scientific, technical, or other specialized
    knowledge will assist the trier of fact to
    understand the evidence or to determine a fact in
    issue, a witness qualified as an expert by
    knowledge,   skill,   experience,  training,   or
    education, may testify thereto in the form of an
    opinion or otherwise.
    The Supreme Court’s decision in Daubert guides the application of
    Rule 702.    As our Court recently summarized:
    [W]hen expert testimony is offered, the trial judge
    must perform a screening function to ensure that
    the expert’s opinion is reliable and relevant to
    the facts at issue in the case. See Daubert, 
    509 U.S. at 589
    , 
    113 S. Ct. at 2794-95
    . Daubert went
    on to make “general observations” intended to guide
    a district court’s evaluation of scientific
    evidence. The nonexclusive list includes “whether
    as might reasonably be contemplated as contributing to the result.”
    Majority Op. at Part IV(c) (citing McClure v. Allied Stores, Inc.,
    
    608 S.W.2d 901
    , 904 (Tex. 1980)).      The fact that there may be
    multiple causes in fact for any given injury does not, however,
    eradicate the requirement of proving but-for causation in this
    case.
    -67-
    67
    [a theory or technique] can be (and has been)
    tested,” whether it “has been subjected to peer
    review and publication,” the “known or potential
    rate of error,” and the “existence and maintenance
    of    standards   controlling    the    technique’s
    operation,” as well as “general acceptance.” 
    509 U.S. at 593-594
    , 
    113 S. Ct. at 2796-97
    .
    Watkins v. Telsmith, Inc., 
    121 F.3d 984
    , 988-89 (5th Cir. 1997).
    A.
    The plaintiffs’ experts’ opinions that the Euclid short-nose
    coal hauler caused the plaintiffs’ back injuries were inadmissible
    primarily because the substance of those opinions was not relevant
    as a matter of law.   Rule 702 permits expert opinion testimony only
    in circumstances in which the opinion “will assist the trier of
    fact to understand the evidence or to determine a fact in issue.”
    For all of the reasons stated in Part III of this dissent, which
    explained that the evidence was not sufficient to prove causation,
    the evidence was furthermore inadmissible under Rule 702 for the
    same reason. Because the substance of the expert opinion testimony
    did not tend to prove causation, it was inadmissible as a matter of
    law because it could not assist the jury.      As the Supreme Court
    explained:
    Faced with a proffer of expert scientific
    testimony, then, the trial judge must determine at
    the outset . . . whether the expert is proposing to
    testify to (1) scientific knowledge that (2) will
    assist the trier of fact to understand or determine
    a fact in issue.      This entails a preliminary
    assessment of whether the reasoning or methodology
    underlying the testimony is scientifically valid
    -68-
    68
    and of whether that reasoning or methodology
    properly can be applied to the facts in issue.
    Daubert, 
    509 U.S. at 592-93
    , 
    113 S. Ct. at 2796
     (footnotes omitted,
    emphasis supplied); see also Daubert v. Merrell Dow Pharms., Inc.,
    
    43 F.3d 1311
    , 1321 n.17, 1320-22 (9th Cir. 1995) (“Federal judges
    must therefore exclude proffered scientific evidence under Rules
    702 and 403 unless they are convinced that it speaks clearly and
    directly to an issue in dispute in the case, and that it will not
    mislead the jury.”); Kenneth R. Foster & Peter W. Huber, Judging
    Science: Scientific Knowledge and the Federal Courts 34-36 (1997);
    cf. Brock v. Merrell Dow Pharms., Inc., 
    874 F.2d 307
    , 311-15 (5th
    Cir. 1989).
    Without belaboring the point, it should be sufficient to note
    the well-established requirement, grounded in Rule 702, that there
    be a “fit” between the opinions offered by an expert and some
    material issue in the case.         If, as in this case, an expert’s
    opinion   is   based   on   reasoning   which   as   a   matter   of   law   is
    insufficient to support the expert’s conclusion, that opinion
    should not be admitted into evidence because, as a matter of law,
    it cannot be helpful to the trier of fact and is therefore
    inadmissible.
    B.
    The plaintiffs’ causation experts’ testimony that the Euclid
    short-nose coal hauler caused the plaintiffs’ back injuries was
    -69-
    69
    also inadmissible because it was not scientifically reliable.                 In
    deciding     Euclid’s     Daubert      challenge,     the   district       court
    acknowledged the factors provided by the Supreme Court, and then
    went on to list factors which it found compelling in this case: the
    witnesses’    credentials;       “a   body   of   literature     dealing    with
    repetitive trauma back injuries"; the fact that the theories could
    be tested; and the fact that the “theories are derived from
    methodology which relates to other accepted methodologies.”25 These
    factors do not adequately ensure the reliability of the experts’
    opinions.
    Though the Supreme Court expressly noted that Daubert’s list
    of factors is nonexclusive, it is certainly significant that the
    testimony    of   Dr.   Aprill   is   plainly     inadmissible    under    those
    original Daubert standards.           The district court found that Dr.
    Aprill’s hypothesis could be tested, but none of the other indicia
    of reliability are present.           The theory has not, in fact, been
    tested.    It has not been subjected to peer review or publication.
    No known or potential rate of error has been provided.              There are
    no standards controlling the technique’s operation.               There is no
    suggestion that Dr. Aprill’s method is generally accepted.
    There is a good reason why almost none of the original Daubert
    criteria are satisfied by Dr. Aprill’s methodology.                It is that
    25
    These supplemental factors were derived from United States v.
    Downing, 
    753 F.2d 1224
     (3d Cir. 1985), a pre-Daubert decision.
    -70-
    70
    there is an entire field of study devoted to the task which he
    attempted.     “Epidemiology is the field of public health that
    studies the incidence, distribution, and etiology of disease in
    human populations and applies the findings to alleviate health
    problems.”      Linda       A.   Bailey   et     al.,    Reference    Guide   on
    Epidemiology, in Reference Manual on Scientific Evidence 123, 125
    (Federal Judicial Center 1994) (emphasis in original).               Dr. Aprill
    did not use epidemiological methodology to come to his conclusions;
    he generated a study for the purposes of this litigation and
    offered an opinion about what it shows.           This is precisely the sort
    of ad hoc method of creating testimony that Rule 702 and Daubert
    exclude.
    The factors relied upon by the district court essentially
    lower the Daubert bar. The court cited the witnesses’ credentials,
    but plainly credentials are not enough.                  The court cited the
    presence of “a body of literature” dealing with the type of
    injuries claimed by the plaintiffs, but that factor completely
    swallows Daubert’s inquiry into peer review and publication.                  As
    Euclid points out, by that reasoning expert testimony about space
    alien abductions would also be admissible.              Likewise, the district
    court’s    reference   to    the   fact   that    the   plaintiffs’    experts’
    “theories are derived from methodology which relates to other
    accepted methodologies” simply lowers the standard set by Daubert’s
    reliance upon “general acceptance.”
    -71-
    71
    In sum, the factors cited by the district court in support of
    admitting the testimony of the plaintiffs’ experts seriously weaken
    the standards of Rule 702 and Daubert.              It was, therefore, an abuse
    of discretion to consider these factors and admit the testimony.
    V.
    With respect to all of the original plaintiffs except Mr.
    Johnny Bartley (who has since settled his claims against Euclid),
    the claims are barred by limitations unless the discovery rule
    applies.      The   jury   found     that    the    plaintiffs’     injuries    were
    inherently undiscoverable and objectively verifiable.                      These are
    the two prerequisites to applying the discovery rule under Texas
    law.    See, e.g., Childs v. Haussecker, 
    974 S.W.2d 31
    , 36 (Tex.
    1998); Computer Assocs. Int’l, Inc. v. Altai, Inc., 
    918 S.W.2d 453
    ,
    456 (Tex. 1994).
    In this case, it is very plain that the plaintiffs’ injuries
    are    not   what   the    Supreme    Court        of   Texas    considers    to   be
    “objectively verifiable.”            “Expert testimony . . . d[oes] not
    supply the objective verification of wrong and injury necessary for
    application of the discovery rule.”            S.V. v. R.V., 
    933 S.W.2d 1
    , 7
    (Tex.   1996).      Objective      verification         is   a   “higher   level   of
    certainty” than the mere preponderance of evidence required to find
    liability.     Cf. 
    id. at 19
    .        For example, a sponge left inside a
    person by a surgeon is objectively verifiable.                      See Gaddis v.
    -72-
    
    72 Smith, 417
     S.W.2d 577 (Tex. 1967).        In the context of a charge of
    sexual   abuse   that   was   “discovered”   after   the   alleged   victim
    recovered repressed childhood memories, the Supreme Court listed
    the kinds of evidence that would qualify as objectively verifiable:
    The kinds of evidence that would suffice would be a
    confession by the abuser, e.g. Meiers-Post v.
    Schafer, 
    170 Mich. App. 174
    , 
    427 N.W.2d 606
    , 610
    (1988); a criminal conviction, e.g. Petersen v.
    Bruen, 
    106 Nev. 271
    , 
    792 P.2d 18
    , 24-25 (1990);
    contemporaneous records or written statements of
    the abuser such as diaries or letters; medical
    records    of    the    person    abused    showing
    contemporaneous physical injury resulting from the
    abuse; photographs or recordings of the abuse; an
    objective eyewitness’s account; and the like. Such
    evidence   would   provide   sufficient   objective
    verification of abuse, even if it occurred years
    before suit was brought, to warrant application of
    the discovery rule.
    S.V., 933 S.W.2d at 15.
    Here, as in Robinson v. Weaver, 
    550 S.W.2d 18
     (Tex. 1977),
    “[e]ven the fact of injury is a matter of expert testimony.”
    Robinson, 550 S.W.2d at 21 (quoted with approval in S.V., 933
    S.W.2d at 7).    There was dispute among the experts at trial as to
    whether there is even such a thing as an “endplate infraction.”
    The following dialogue occurred when Euclid cross-examined Dr.
    Aprill at trial about his interpretations of the plaintiffs’ MRI
    scans:
    Q    Now, sir, isn’t it true that the vast majority
    of the articles that either you’ve written alone or
    with other people, that the vast majority of these
    articles have two radiologists, or at least two
    radiologists, to look over the same scans that are
    -73-
    73
    the subject of those articles in order to see if
    the radiologists agree with the interpretations?
    A    No, that is not true.
    Q    Well, sir, do you think that there’s a problem
    or that there’s something wrong about having work
    checked over to see if your interpretation of an
    MRI is the same as somebody else’s?
    A    No, I don’t.
    Q     Have you had a radiologist, other than
    yourself, look over your interpretations of these
    MRIs in order to see if they agree with what you
    said?
    A    No, I have not.
    Q    But radiologists other than you have reviewed
    these MRIs, have they not, sir?
    A    I don’t know.
    Q     Have you not seen the reports done by Dr.
    Gallman, the chief of radiology at Schumpert
    Hospital, concerning your interpretation of these
    MRIs?
    A    I saw his review of the interpretation of five
    of the MRIs. There are 165 scans done, and I think
    he commented on five.
    Q    We are talking about the five Plaintiffs in
    this case, he commented upon those, did he not?
    A    Yes.   Yes, he did.
    Q    And he disagreed with many of the things you
    said, did he not sir?
    A    Yes, he did.
    Q    And he disagreed with the importance that you
    placed on some of the things that you found, did he
    not, sir?
    A    Yes, he did.
    -74-
    74
    Q    And he disagreed with your opinions in this
    case, did he not?
    A    Yes, he did.
    Q     Would you agree with me, sir, that different
    radiologists have different styles interpreting
    MRIs?
    A    Yes, they do.
    Q    I want to show you a statement out of the “New
    England Journal of Medicine” . . . and ask if you
    agree with this. . . . “This new study is also a
    reminder that the interpretation of MRI findings
    can vary substantially so that the results may be
    equivocal    despite   the    techniques    or   of
    infallibility.   Thus, for example, Jensen, et al
    found that one expert neuroradiologist was 30
    percent more likely to interpret a study as showing
    a   disc   protrusion    than   a   second   expert
    neuroradiologist reading the same films.       This
    variation, although no worse than that for many
    other complex, clinical tests requiring expert
    interpretation, creates further opportunities for
    erroneous clinical decisions.”     Would you agree
    with that?
    A    Yes.
    Q    Some radiologists think certain things are
    abnormal and some don’t, is that fair to say?
    A    Yes.   Yes.
    Q    And there are a number of things that you
    claim are abnormal on the MRIs of these Plaintiffs
    here which other doctors do not think are abnormal;
    isn’t that right, sir?
    A    I don’t know that for a fact. The only person
    that I know that has commented on them is the
    doctor that you mentioned.
    The point was illuminated when Euclid presented its case.   A
    hospital’s chief radiologist presented as an expert witness, Dr.
    William H. Gallman, III, had reviewed the plaintiffs’ MRIs.     He
    -75-
    75
    testified that there was absolutely nothing unique or abnormal
    about them.            He further commented that although his practice
    involved daily reviews and interpretations of MRIs, he had never
    seen     or     heard   the   term   “endplate   infraction,”    none   of   his
    colleagues had seen or heard it, and he believed that Dr. Aprill
    had fabricated the concept for the purpose of this litigation.               The
    phenomenon referred to by Dr. Aprill as an endplate infraction is,
    in the opinion of Dr. Gallman, “extremely common,” having “no
    significance” and seen “every day on multiple studies of different
    patients of all walks of life.”           Another of Euclid’s experts, Dr.
    Malcolm       Pope,     distinguished   professor   in   the   Departments    of
    Biomedical Engineering, Orthopedic Surgery, Preventative Medicine,
    and Mechanical Engineering at the University of Iowa, testified
    that endplate infractions are “not a widely accepted abnormality”
    and that “[s]ome radiologists would not even report it.”
    Where even the fact of injury is disputed, and contested
    expert testimony provides the only explanation for the cause of
    that injury, it is impossible to conclude that the injury is
    “objectively verifiable.”            The discovery rule is an exception to
    Texas statutes which otherwise limit the period of time in which
    plaintiffs may seek redress for injuries.                The Supreme Court of
    Texas has made it clear that the discovery rule is not justified in
    cases where the injury cannot be demonstrated by clear physical
    evidence.          The plaintiffs’ claims in this case are time-barred
    g:\opin\97-40365.dis                    -76-
    76
    because they do not meet that high prerequisite to the application
    of the discovery rule.
    VI.
    For the foregoing reasons, the judgment of the district court
    should be reversed and judgment should be rendered in favor of
    Euclid.   Accordingly, I dissent from the panel majority’s contrary
    conclusion.
    -77-
    77
    

Document Info

Docket Number: 97-40365

Citation Numbers: 158 F.3d 261

Judges: DeMOSS, Parker, Reavley

Filed Date: 11/3/1998

Precedential Status: Precedential

Modified Date: 8/1/2023

Authorities (29)

United States v. John W. Downing , 753 F.2d 1224 ( 1985 )

Joyce Wells v. Hico Independent School District, Etc., ... , 736 F.2d 243 ( 1984 )

Michael Jones and Harold Jones v. Wal-Mart Stores, Inc., ... , 870 F.2d 982 ( 1989 )

aero-international-inc-a-mississippi-corporation-v-united-states-fire , 713 F.2d 1106 ( 1983 )

Teddy Gutierrez, and Pamela Calderon Maria De La Cruz v. ... , 106 F.3d 683 ( 1997 )

Ernest Mosley v. Excel Corporation , 109 F.3d 1006 ( 1997 )

Luke Joseph Perricone, United States Fidelity and Guaranty ... , 704 F.2d 1376 ( 1983 )

Jules R. Viterbo, Et Ux, (Patricia Viterbo) v. The Dow ... , 826 F.2d 420 ( 1987 )

Moore v. Ashland Chemical Inc. , 151 F.3d 269 ( 1998 )

betty-lou-martin-individually-and-as-next-friend-of-kimberly-rene-martin , 726 F.2d 207 ( 1984 )

jo-ann-mccann-and-blanche-christine-hickman-blanche-christine-hickman , 984 F.2d 667 ( 1993 )

john-g-denton-and-paula-j-savage-plaintiffs-appellees-cross-appellants , 136 F.3d 1038 ( 1998 )

crosthwait-equipment-co-inc-crosthwait-equipment-company-inc-a , 992 F.2d 525 ( 1993 )

Ouida McCandless Cross v. Beech Aircraft Corporation, Cross , 779 F.2d 220 ( 1985 )

Albert E. Albertson v. T.J. Stevenson & Company, Inc. , 749 F.2d 223 ( 1984 )

Mr. And Mrs. Floyd Brock, Individually and as Next Friend ... , 874 F.2d 307 ( 1989 )

Paul D. Fairley v. American Hoist & Derrick Company, Etc. , 640 F.2d 679 ( 1981 )

Joanne Ayres v. Sears, Roebuck & Company , 789 F.2d 1173 ( 1986 )

Natalia Flores v. Cameron County, Texas, Cameron County, ... , 92 F.3d 258 ( 1996 )

Greenwood v. Societe Francaise De , 111 F.3d 1239 ( 1997 )

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