Patricia Hughes v. Kia Motors Corporation , 766 F.3d 1317 ( 2014 )


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  •                Case: 13-10922       Date Filed: 09/12/2014       Page: 1 of 31
    [PUBLISH]
    IN THE UNITED STATES COURT OF APPEALS
    FOR THE ELEVENTH CIRCUIT
    ________________________
    No. 13-10922
    ________________________
    D.C. Docket No. 1:11-cv-02733-JOF
    PATRICIA HUGHES,
    Mother and Administratrix of the
    Estate of Allene J. Hughes
    Plaintiff - Appellant,
    versus
    KIA MOTORS CORPORATION,
    KIA MOTORS AMERICA, INC.
    Defendants - Appellees.
    ________________________
    Appeal from the United States District Court
    for the Northern District of Georgia
    ________________________
    (September 12, 2014)
    Before TJOFLAT and WILSON, Circuit Judges, and BUCKLEW, ∗ District Judge.
    ∗
    Honorable Susan C. Bucklew, United States District Judge for the Middle District of
    Florida, sitting by designation.
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    TJOFLAT, Circuit Judge:
    On May 2, 2005, Allene Hughes was involved in a vehicle collision with a
    Mack truck in Chattanooga, Tennessee. The collision sent her Kia Optima
    pinballing about, colliding with two parked cars, a fence, a tree, three metal posts
    supporting a carport awning, and a flag pole before ultimately coming to rest
    against a house. On May 3, Allene was declared dead from traumatic brain injury.
    Patricia Hughes, Allene’s mother and the administratrix of her estate, filed
    suit against Kia Motors Corporation and Kia Motors America, Inc. (collectively,
    “Kia”) in Georgia Superior Court, alleging that Kia’s failure to equip the Optima
    with a fuel shut-off switch led to Allene’s death. Kia removed the case to federal
    court,1 and discovery commenced. When discovery closed, Kia moved to exclude
    the testimony of Hughes’s causation expert, Dr. Joseph L. Burton, and also moved
    for summary judgment. The District Court granted both of Kia’s motions. Hughes
    now appeals. Because the court did not abuse its discretion in excluding Burton’s
    testimony and did not improperly grant summary judgment in Kia’s favor, we
    affirm.
    1
    Kia asserted diversity jurisdiction under 28 U.S.C. § 1332, as the parties were citizens
    of different states and the amount in controversy exceeded $75,000. Hughes is a resident of
    Georgia, Kia Motors Corporation is a foreign national corporation organized under the laws of
    the Republic of Korea and having its headquarters and principal place of business in Seoul,
    South Korea, and Kia Motors America, Inc. is incorporated under California law with its
    principal place of business in California.
    2
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    I.
    Allene Hughes died as a result of injuries she incurred from a vehicle
    collision in Chattanooga, Tennessee, at 2:45 a.m. on May 2, 2005. That night,
    Allene drove her 2004 Kia Optima out of a Waffle House parking lot onto Club
    Drive, a one-way street. However, Allene exited the parking lot in the wrong
    direction, and ended up traveling against the correct direction of traffic (no other
    cars were on the Club Drive at the time). Upon realizing her mistake and reaching
    the intersection of Moore and Brainerd Roads, Allene entered the through lanes of
    Brainerd Road and was struck by the front of a westbound Mack truck pulling a
    loaded fuel tanker trailer.
    After impact, the Mack truck came to a stop in the intersection. The Optima
    traveled farther. The Optima initially traveled south, entering the property of a gas
    station and convenience store. It then turned back toward the north, crossing all
    the lanes of Brainerd Road and entering the parking lot of the Waffle House. In
    the parking lot, the Optima struck a parked Geo Tracker and a parked Toyota
    Corolla. It then ran through a fence to the north of the Waffle House, entering
    Club Drive, and traveled east onto residential property. There, the Optima
    sideswiped a tree in the front yard and struck three support posts of a carport
    awning and a flagpole. The Optima came to a rest against the house.
    3
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    The diagram below, which the police officers who arrived on the scene
    created, indicates the Optima’s movement from the moment it left the Waffle
    House until it came to a rest against the house. In the diagram, Allene’s vehicle is
    indicated with the number 1, the Mack truck is number 2, and the Geo Tracker and
    Toyota Corolla are indicated with numbers 3 and 4.
    DE 68-12, at 5.
    4
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    When the Emergency Medical Service (“EMS”) arrived on the scene, Allene
    had already been removed from the Optima. She was unresponsive, but was
    breathing four to six times per minute with the assistance of a bag-valve mask.
    EMS reported that her only obvious injury was an abrasion to the left knee.
    EMS transported Allene to Erlanger Medical Center, where doctors
    discovered evidence of traumatic brain injury, left frontal subdural hematoma, and
    epidural right pulmonary contusion. She also had suffered a pelvic fracture. An
    emergency craniotomy and implantation of a Scott cannula to drain the blood from
    subdural cavity was unsuccessful. Allene was brain dead. At 2:30 p.m. on May 3,
    Allene was declared dead.
    II.
    On July 15, 2011, Patricia Hughes, Allene’s mother and the administratrix of
    her estate, filed a wrongful death action against Kia in the Superior Court of
    Gwinnet County, Georgia. The complaint included two theories of liability: strict
    liability for the inherently dangerous design of the Optima and negligence based on
    alleged defects in the Optima’s airbag deployment system, its lack of a fuel flow
    shut-off device, Kia’s failure to warn of the unreasonable dangers inherent in the
    design of the Optima, and Kia’s failure to remedy the defective condition of the
    Optima.
    5
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    Kia filed a timely notice of removal, pursuant to 28 U.S.C. § 1446(b), in the
    United States District Court for the Northern District of Georgia. After Kia filed
    its answer to the complaint’s allegations and affirmative defenses, the case
    proceeded to discovery.
    A.
    Hughes hired Ralph Cunningham, an accident reconstructionist, 2 who
    prepared a report on the collision between the Optima and the Mack truck.
    According to the Mack truck’s Engine Control Module, which makes a permanent
    record of a vehicle’s speed before and shortly after a hard breaking event, the
    Mack truck approached the intersection where the collision occurred at 39 miles
    per hour (mph). When the driver applied the brakes, the truck began to rapidly
    decelerate at a steady speed until the truck came to a stop. Cunningham estimated
    that the truck was traveling at a speed of not less than 10 mph and not more than
    24 mph when it struck Allene’s Optima.
    Cunningham’s report indicates that the truck struck the Optima at 12 degrees
    forward of perpendicular to the left side. For point of reference, a collision that is
    perpendicular to the left side—a T-bone collision—would be 0 degrees. A head-on
    2
    Cunningham has a B.S.E. degree from Century University, an Engineer in Training
    certification, and full accreditation as a Traffic Accident Reconstructionist.
    6
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    collision would be 90 degrees. Thus, the collision was closer to perpendicular than
    head-on.
    When the vehicles collided, the Optima’s driver’s side airbag deployed.
    Although the Optima was originally equipped with a driver’s front airbag, it had
    deployed at some point prior to the May 2 collision and was not replaced; the
    deployed airbag had been cut away from the steering wheel. The region of greatest
    permanent deformation coincided with the left “A” pillar and front-door hinge
    region, where the inward crush was 20 inches. The crush diminished toward the
    rear, and scrapes on the left rear door and back of the Optima indicated sliding
    contact, which Cunningham opined was likely from the vehicles separating from
    each other. The brake pedal jammed such that it could not be applied, and it
    deformed toward the right side of the vehicle, jamming the throttle pedal in an
    applied position.
    Cunningham calculated the total delta-v—which represented the sudden
    change in velocity that occurred during the contact phase of the collision with the
    Mack truck—as 37.5 mph. Because the collision was neither head-on nor perfectly
    perpendicular, the total delta-v could be separated into its longitudinal and lateral
    7
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    components. Cunningham calculated the longitudinal delta-v using the total delta-
    v, the 12 degree angle of impact, and simple trigonometry. 3
    From his calculations, Cunningham concluded that the longitudinal delta-v,
    the sudden change in velocity in the longitudinal direction during the contact phase
    of the collision, equaled approximately 8 mph. Cunningham did not calculate
    lateral delta-v—the change in velocity along the perpendicular plane—because
    Hughes’s attorneys did not request that he do so.
    Cunningham estimated the Optima’s probable post-impact travel if it had
    been equipped with a fuel shut-off device by using two estimated speeds at which
    the Optima could have been traveling when it collided with the Mack truck—38
    mph and 26 mph. 4 Based on these two speeds, Cunningham predicted that the
    Optima would have traveled between 69 and 98 feet if it had been traveling 38
    3
    The calculation can be expressed as follows:
    = sin 12°
    longitudinal delta v
    = sin 12°
    total delta v
    longitudinal delta v
    longitudinal delta v = sin 12° (37.5 mph)
    37.5 mph
    longitudinal delta v ≈ 8 mph
    4
    Cunningham estimated using the maximum rate of acceleration possible for the Optima
    and a lesser rate of acceleration of five feet per second per second. Cunningham believed that
    even a speed of 26 using this lower acceleration rate was “somewhat improbably high,” DE 110,
    at 9, but he did not calculate the Optima’s velocity using any other acceleration rate.
    8
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    mph, and between 32 and 46 feet if it had been traveling at 26 mph. Had it
    traveled the longer distance, the Optima would have stopped roughly on the curb
    of the northwest corner of the gas station and convenience store. Had the Optima
    been traveling at 26 mph, it would have come to a rest on Brainerd Road in the
    eastbound lanes.
    B.
    Hughes also hired a medical expert, Dr. Joseph Burton, 5 to determine
    Allene’s cause of death. His report concluded that Allene “died of blunt force
    trauma that occurred predominantly to the left side of her head.” DE 63-2, at 4.
    He further concluded, based extensively on Cunningham’s report, that
    the fact that the [Optima] did not stop operating in a timely manner
    after the initial impact with the Mack Truck was contributory or
    causative of [Allene’s] brain injuries. . . . [H]ad the [Optima] stopped
    in a timely manner and did not have the additional impact it is more to
    a reasonable degree of forensic, medical, and scientific probability
    that [Allene] would not have sustained a fatal brain injury.
    DE 63-2, at 10. Burton suggested that “[t]he dynamics of the left/frontal collision
    with the Mack Truck combined with the deploying side airbag would have caused
    [Allene’s] body to move forward towards the intrusion [at the A-pillar] and
    5
    Dr. Burton has an M.D. degree from Emory University Medical School. He is board
    certified in forensic pathology. He has been chief medical examiner in several counties, a
    clinical professor in forensic pathology and director of forensic pathology training program at the
    Emory University Medical School.
    9
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    leftward interacting with the side impact airbag.” DE 63-2, at 9. Based on these
    dynamics, Burton opined that “[i]t is possible that [Allene] sustained her left sided
    brain injury in this impact due to her body moving forward past the deployed torso
    bag and her head interacted with the intruding structures of the [Optima].” DE 63-
    2, at 9. As the Optima impacted other objects and the various curbs, Allene’s body
    “would have the opportunity to have interaction of her head with the steering
    wheel (due to there being no airbag there to prevent interaction) and the instrument
    panel in a manner which would either exacerbate or potentially cause her brain
    injury.” DE 63-2, at 9.
    Thus, Burton summarized, Allene “could have sustained her brain injury in
    the first impact and then due to subsequent impacts her head and body could have
    interacted in a manner that would have exacerbated the brain injury she already
    received.” DE 63-2, at 11. Alternatively, Allene “could have possibly sustained
    the brain injury that caused her death as a result of her head’s contact with the
    steering wheel and/or instrument panel during the additional impacts the [Optima]
    experienced as a result of not stopping in a timely manner.” DE 63-2, at 11.
    Burton explained in his report that a specific error rate for clinical
    impressions is difficult to calculate, but he held his opinion “to a reasonable degree
    of forensic and scientific medical probability and certainty.” DE 63-2, at 11.
    Burton explained that his conclusions were “supported by extensive references to
    10
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    the literature, to research and to 30 years of training, education and experience.”
    DE 63-2, at 12. He further indicated that his opinions were “based on the specific
    data [he] evaluated, the condition of the subject vehicle which [he] personally
    inspected, [his] personal evaluation of various photographic evidence submitted
    with the case file and on [his] education, background and training.” DE 63-2, at
    13.
    Burton assured that the methodology he employed “comport[ed] to the
    scientific method of inquiry.” DE 63-2, at 13. He explained that the scientific
    method involves stating the problem, collecting data, formulating a hypothesis,
    validating the hypothesis, and considering the potential for error.
    C.
    When Kia deposed Dr. Burton on May 3, 2012, he described his
    methodology for reaching his opinion. Burton explained that he assessed the
    forces that acted on the Optima, “[n]ot only how much they were, but where they
    were coming from and how they were impacting in this case the package the
    person was in, the [Optima] in this case.” DE 67-1, at 13. Burton opined that
    “[w]e’re not dealing with some kind of high delta-v, high g-force crash.” DE 67-1,
    at 22. Burton explained that, according to the National Highway Traffic Safety
    Administration (the “NHTSA”), “if the delta-v is over 26, they consider it a severe
    impact,” whereas a delta-v of 0 to 10 is “minor.” DE 67-1, at 22.
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    Kia asked Burton about his impression of the collision between the Optima
    and the Mack truck, and he explained that the collision was 12 degrees forward of
    a 90-degree side impact and “resulted in a delta-v for the [Optima] of about . . . 8
    miles an hour.” DE 67-1, at 26. Burton described the pulse, or time of impact, as
    “relatively short[,] like less than a hundred milliseconds.” DE 67-1, at 26. He
    reasoned that “it is a big truck hitting a little car but it is not hitting it when it is
    going very fast and it resulted in what would be, according to NHTSA, a low or
    minor delta-v to the [Optima].” DE 67-1, at 26. Burton acknowledged that the 8
    mph he referred to was actually the longitudinal delta-v, not the total or lateral
    delta-v, but he opined that “delta-v is not the most important factor” in predicting
    injury for a side impact. DE 67-1, at 26–27.
    Instead, Burton explained that the two most important factors for predicting
    injury for a side impact are amount of intrusion into the interior of the Optima and
    the velocity of the adjacent door panel. Burton said that he believed that
    Cunningham’s report said that the Mack truck had slowed to approximately 12
    mph, which meant “the front of the truck is moving at 12 miles an hour which
    means at some point in time the door panel or part of the [Optima], its interior, will
    be moving at approximately 12 miles an hour also.” DE 67-1, at 27–28. We pause
    here to note two things. First, Cunningham’s report actually said the truck had
    slowed to between 10 and 24 mph when it struck the Optima; the report never said
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    the truck was traveling at 12 mph when it impacted the Optima. Second, and more
    importantly, Burton’s explanation demonstrates that he measured the velocity of
    the adjacent door panel as equal to the speed at which the truck was traveling at
    impact.
    Kia’s attorney then asked Burton to assume that Cunningham had calculated
    that lateral delta-v during his deposition, which was taken earlier. 6 Burton was
    asked to assume that lateral delta-v was approximately 37 mph. Then, Kia’s
    attorney asked Burton for the velocity of the Optima’s interior door resulting from
    the impact with the truck, to which Burton repeated his earlier calculation, which
    he reached based on Cunningham’s report, of 12 mph. Burton then said, “If I
    assume hypothetically that [the truck] hit [the Optima] at 36 miles an hour or 35,
    then at some point in time part of the interior structure of the [Optima] was moving
    at that speed.” DE 67-1, at 33. Notably, Burton assumed that the 35 or 36 mph
    represented the truck’s velocity at the moment of impact, rather than lateral delta-
    6
    In fact Cunningham had been asked to do so. Using the angle of impact, the total delta-
    v, and trigonometry, he calculated lateral delta-v as approximately 37 mph. The equation below
    = cos 12°
    demonstrates how Cunningham arrived at lateral delta-v.
    lateral delta v
    = cos 12°
    total delta v
    lateral delta v
    lateral delta v = cos 12° (37.5 mph)
    37.5 mph
    lateral delta v ≈ 37 mph
    13
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    v. 7 Then relying on that assumption about the Mack truck’s velocity—which was
    different than the assumption Kia’s attorney asked Burton to make—he calculated
    the interior velocity as equivalent to the truck’s assumed velocity.
    Kia’s attorney followed Burton’s response by asking, “[I]f the assumption
    you’re making of Mr. Cunningham making that approximately 37-mile-per-hour
    delta-v is in fact true, you would now agree with me that at some point in that
    impact between the [Optima] and the Mack Truck part of that driver’s door was
    traveling at least 35 miles per hour. Is that fair?” DE 67-1, at 33. Pause for a
    moment to recognize that by asking about lateral delta-v—rather than the velocity
    of the truck at impact—Kia’s attorney changed the thing being measured and asked
    if it would support the same conclusion. In other words, Burton appears to have
    assumed that the truck’s velocity would be equivalent to the Optima’s interior
    velocity at the moment of impact, whereas Kia’s attorney asked if the Optima’s
    lateral delta-v, its lateral change in velocity, would equal the Optima’s interior
    velocity. But the truck’s velocity and the Optima’s lateral delta-v are different
    measurements, and Burton likely should have recognized as much. Apparently
    missing this sleight of hand, however, Burton agreed with Kia’s attorney that a
    7
    Cunningham never calculated the truck’s actual velocity at the moment of impact; he
    estimated the truck’s velocity was between 10 and 24 mph.
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    delta-v of approximately 37 mph would result in an interior velocity of at least 35
    mph.
    During his deposition, Burton agreed that if lateral delta-v exceeded 35 mph,
    it “could have caused a fatal brain injury.” DE 67-1, at 43. He further stated that
    he would hold that opinion to a reasonable degree of medical certainty. Then, the
    following colloquy occurred between Kia’s attorney and Burton:
    Q: But as I parse those words, you’re not of the opinion that the
    impact between the Mack truck and the [Optima] in fact was the
    impact that was the cause of her fatal injury in this case?
    A: My opinion is that I don’t know enough about the other impacts to
    exclude them. . . . So I know those are all possibilities. And did that
    happen here versus the Mack truck impact? I don’t know. I’m
    certainly not going to embarrass myself by arguing with somebody
    that the Mack truck impact couldn’t produce a fatal injury because I
    would look ridiculous and whatever credibility I might have to a jury
    or to a court I would lose if I tried to say that there’s no way that
    Mack truck impact could have killed this lady. I wouldn’t say that.
    DE 67-1, at 43–44.
    Burton conceded that he lacked sufficient information to conclude that the
    impact with the Toyota Corolla or the Geo Tracker—the two cars the Optima
    collided with in the Waffle House parking lot—caused the fatal brain injury. He
    also conceded that he could not conclude whether Allene received her injuries
    from the side airbag, the A pillar, or the steering wheel rim, admitting that “[a]ll
    three have the capacity to cause her brain to look the way it looks. But they all had
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    the capacity to leave no telltale sign of interaction with the structure either.” DE
    67-1, at 56. Kia’s attorney followed up:
    Q: So for all of the other impacts other than the Mack truck, you don’t
    have enough acceleration or deceleration information to make an
    analysis with respect to those impacts and the likelihood that during
    one of those impacts Ms. Hughes impacted some part of the [Optima];
    is that correct?
    A. Well, I know enough about curb impacts and things like that to
    know that it has the potential to cause her injury and to have her
    impact a structure from it. Did it and what structure was it, I don’t
    have enough information to answer that part of the equation.
    DE 67-1, at 64–65.
    Nevertheless, Burton reaffirmed toward the end of his deposition that he
    held the opinion that it was “more likely than not that” Hughes’s brain injury was
    caused by some event after impact with the Mack truck because he believed the
    side airbag “offered her significant protection in that Mack truck impact.” DE 67-
    1, at 71.
    III.
    A.
    Kia moved to exclude Burton’s testimony, arguing that Burton’s opinion
    was not the product of reliable methodology and it did not fit the evidence in the
    case. Specifically, Kia noted that Burton had admitted during his deposition that
    the velocity of the interior of the door being impacted is a critical factor to
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    analyzing the collision. But, Kia argued, Burton ignored lateral delta-v in forming
    his opinion. According to Kia, because he ignored lateral delta-v, Burton
    incorrectly assumed that the interior velocity of the door was 12 mph. Kia pointed
    to Burton’s deposition, in which he agreed with Kia’s attorney that if lateral delta-v
    were approximately 37 mph, the interior velocity of the door would have been at
    least 35 mph. Kia also pointed to Burton’s deposition statement that if lateral
    delta-v were 37 mph, it could cause a fatal brain injury.
    Kia also argued that Burton’s opinion should be excluded because he failed
    to properly employ differential diagnosis as part of his methodology. According to
    Kia, Burton could not exclude the impact by the Mack truck as the cause of the
    fatal brain injury and did not have sufficient information about the other impacts to
    know whether Allene would have collided with any of the interior structures of the
    Optima. As such, he could not include any of the other impacts as part of his
    analysis in trying to determine causation.
    Hughes opposed Kia’s motion, arguing that while considering lateral delta-v
    may be relevant to the question of whether, as a general matter, a high lateral delta-
    v can cause death, it does not establish whether Allene actually received her fatal
    injury from the collision with the Mack truck. Hughes contended that Burton’s
    methodology was sound because it considered the actual Optima damage and
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    protection from the side airbag, just without a calculation of lateral delta-v. 8
    Hughes then argued that, under Tennessee law, 9 she need only prove that the
    Optima’s design defect was a substantial factor in causing Allene’s death. In other
    words, Burton was not required to exclude other causes of Allene’s death. Hughes
    pointed to Burton’s deposition testimony where he stated that he believed the side
    airbag provided significant protection in the Mack truck impact, and she argued
    that this demonstrated that Burton possessed sufficient information to determine
    that later impacts caused Allene’s death.
    Kia replied that, under Tennessee law, causation refers to both cause in-fact
    and proximate cause, and therefore Hughes was required prove that the collision
    with the Mack truck was not the cause in-fact of her death. Because Burton could
    not do so, Kia argued, his causation opinion should be excluded.
    8
    Hughes also relied on information contained in Burton’s supplement to his original
    expert report and in his declaration, both of which were filed along with Hughes’s opposition to
    Kia’s motion to exclude Burton’s testimony. Kia moved to strike those two filings, and the
    District Court granted Kia’s motion. Hughes does not challenge the propriety of the District
    Court’s striking Burton’s supplement and declaration. Therefore, we ignore those filings and the
    contentions contained therein for purposes of this appeal. See United States v. Pilati, 
    627 F.3d 1360
    , 1364 (11th Cir. 2010) (“[W]hen on appeal a [party] fails to raise an issue when the
    opportunity is presented, he waives that argument.”).
    9
    Georgia applies the choice-of-law principle lex loci delicti, which means apply the law
    of the place where the tort was committed. See Dowis v. Mud Slingers, Inc., 
    279 Ga. 808
    , 816,
    
    621 S.E.2d 413
    , 419 (2005). Therefore, in this case we apply Tennessee law.
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    The District Court agreed with Kia and granted its motion to exclude
    Burton’s testimony. Specifically, the court concluded that Tennessee law required
    that Hughes demonstrate actual causation, and thus the lack of a shut-off switch
    could not be a substantial factor in Allene’s fatal injury if she sustained that injury
    on impact with the Mack truck. The court faulted Burton for failing to explain
    how the scientific method assisted him in reaching his opinion; Burton simply
    stated that he used the scientific method. The court also reasoned that in light of
    Burton’s deposition admission that he would need to consider the forces acting on
    the injured person, his failure to consider lateral delta-v demonstrated a failure to
    follow his stated methodology. Finally, the District Court noted that Burton
    admitted that a delta-v of 35 mph could have caused a fatal brain injury, and, after
    he was informed that lateral delta-v in this case was 37 mph, that the interior
    velocity of the driver’s side door would be at least 35 mph.
    The District Court also found fault in Burton’s failure to attempt to falsify
    his conclusions. 10 Because Burton could not rule out the initial impact as the cause
    10
    The court expressed such failure in its dispositive order:
    [P]art of the scientific method is attempting to falsify one’s conclusions.
    Defendants correctly argue that Dr. Burton was neither able to rule out the initial
    impact with the tractor trailer as the cause of Ms. Hughes’s fatal brain injury, nor
    was he able to identify any particular impact after the tractor trailer which might
    have caused a fatal brain injury. Dr. Burton readily admitted that he did not know
    enough about the other impacts the [Optima] sustained after the initial impact
    19
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    of the fatal injury and because he could not identify any particular impact after the
    Mack truck collision that might have caused the injury, his opinion was unreliable.
    Based on these problems with Burton’s opinion, the court ruled his opinion
    inadmissible.
    B.
    At the same time it filed a motion to exclude Burton’s testimony, Kia filed a
    motion for summary judgment, which the District Court granted. The court
    determined that Hughes presented no evidence that Allene either did or did not
    suffer her fatal brain injury at the time of the impact with the Mack truck. Even if
    Burton’s testimony were admitted, the court said it would still find that Kia would
    be entitled to summary judgment because Hughes could not demonstrate proximate
    causation. The parties agreed that the front air bag did not deploy because it had
    deployed in a previous accident and was never replaced. Thus, the court held,
    there was no evidence in the record from which a reasonable juror could conclude
    that the lack of a shut-off switch caused Allene’s fatal injuries.
    with the tractor trailer to determine whether Ms. Hughes suffered her fatal brain
    injury at any other point in the sequence of events.
    DE 98, at 18–19 (citation omitted).
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    IV.
    We review the District Court’s exclusion of Burton’s expert testimony under
    an abuse-of-discretion framework. Gen. Elec. Co. v. Joiner, 
    522 U.S. 136
    , 142–43,
    
    118 S. Ct. 512
    , 517, 
    139 L. Ed. 2d 508
    (1997). “[T]his standard of review requires
    that we defer to the district court’s evidentiary ruling unless that ruling is
    ‘manifestly erroneous.’” Quiet Tech. DC-8, Inc. v. Hurel-Dubois UK Ltd., 
    326 F.3d 1333
    , 1340 (11th Cir. 2003) (quoting 
    Joiner, 522 U.S. at 142
    , 118 S. Ct. at
    517). “Because the task of evaluating the reliability of expert testimony is
    uniquely entrusted to the district court . . . we give the district court ‘considerable
    leeway’ in the execution of its duty.” Rink v. Cheminova, Inc., 
    400 F.3d 1286
    ,
    1291 (11th Cir. 2005) (citation omitted) (quoting Kumho Tire Co. v. Carmichael,
    
    526 U.S. 137
    , 152, 
    119 S. Ct. 1167
    , 1176, 
    143 L. Ed. 2d 238
    (1999)).
    The admission of expert evidence is governed by Federal Rule of Evidence
    702, which provides:
    A witness who is qualified as an expert by knowledge, skill,
    experience, training, or education may testify in the form of an
    opinion or otherwise if:
    (a) the expert’s scientific, technical, or other specialized knowledge
    will help the trier of fact to understand the evidence or to determine a
    fact in issue;
    (b) the testimony is based on sufficient facts or data;
    21
    Case: 13-10922     Date Filed: 09/12/2014    Page: 22 of 31
    (c) the testimony is the product of reliable principles and methods;
    and
    (d) the expert has reliably applied the principles and methods to the
    facts of the case.
    Rule 702 and the Supreme Court’s decisions in Daubert v. Merrell Dow Pharm.,
    Inc., 
    509 U.S. 579
    , 
    113 S. Ct. 2786
    , 
    125 L. Ed. 2d 469
    (1993), and its progeny
    make clear that district courts act as gatekeepers, excluding evidence unless is it
    reliable and relevant. “District courts are charged with this gatekeeping function
    ‘to ensure that speculative, unreliable expert testimony does not reach the jury’
    under the mantle of reliability that accompanies the appellation ‘expert
    testimony.’” 
    Rink, 400 F.3d at 1291
    (quoting McCorvey v. Baxter Healthcare
    Corp., 
    298 F.3d 1253
    , 1256 (11th Cir. 2002)). Whether an expert’s testimony is
    reliable depends on “the particular facts and circumstances of the particular case.”
    Kumho Tire 
    Co., 526 U.S. at 158
    , 119 S. Ct. at 1179.
    This court has set out three requirements that an expert must meet before his
    opinions may be admitted. First, the expert must be qualified on the matter about
    which he intends to testify. City of Tuscaloosa v. Harcros Chemicals, Inc., 
    158 F.3d 548
    , 562 (11th Cir. 1998). Second, he must employ reliable methodology.
    
    Id. Third, the
    expert’s testimony must be able to assist the trier of fact through the
    application of expertise to understand the evidence or fact in issue. 
    Id. With respect
    to whether an expert’s methodology is reliable, we look to a number of
    22
    Case: 13-10922     Date Filed: 09/12/2014    Page: 23 of 31
    factors, including (1) whether the methodology can be and has been tested, (2)
    whether the theory or technique has been subjected to peer review, (3) the known
    or potential rate of error of the methodology employed, and (4) whether the
    methodology is generally accepted. 
    Daubert, 509 U.S. at 593
    –94, 113 S. Ct. at
    2797. This list of factors is not meant to be exhaustive, nor must each factor be
    present in a given case. The proponent of the expert opinion must carry the burden
    of establishing qualification, reliability, and helpfulness. United States v. Frazier,
    
    387 F.3d 1244
    , 1260 (11th Cir. 2004) (en banc).
    Our opinion in Frazier, is instructive, because there, as here, the expert
    “offered precious little in the way of a reliable foundation or basis for his opinion.”
    
    Id. at 1265.
    In that case, the defendant sought to introduce expert testimony on the
    transfer of hairs and bodily fluids during sexual assault. 
    Id. at 1252.
    The expert
    was prepared to testify that no hair or bodily fluids were discovered at the crime
    scene, and therefore it was unlikely the defendant had sexually assaulted the
    alleged victim. 
    Id. The Government
    moved to exclude the expert’s testimony, and
    the District Court did so after holding a Daubert hearing. 
    Id. at 1252–56.
    Sitting as en banc, we affirmed the District Court’s exclusion of the expert’s
    testimony, concluding that although the expert was qualified, his methodology was
    not reliable and his opinion would not have been helpful to the jury. 
    Id. at 1264–
    66. With respect to reliability, we explained that the expert had based his opinion
    23
    Case: 13-10922      Date Filed: 09/12/2014    Page: 24 of 31
    on “his experience, and on various texts in forensic investigation.” 
    Id. 1265. The
    problem, however, was that the expert never explained how his experience or the
    relevant texts supported his opinion. 
    Id. Because the
    basis for the opinion was left
    unstated, “it would be very difficult indeed for the district court (or for that matter
    the jury) to make even an informed assessment, let alone to verify” that the opinion
    was reliable. 
    Id. We held,
    Since [the expert] was relying solely or primarily on his experience, it
    remained the burden of the proponent of this testimony to explain how
    that experience led to the conclusion he reached, why that experience
    was a sufficient basis for the opinion, and just how that experience
    was reliably applied to the facts of the case.
    
    Id. Having failed
    to do so, we concluded that the district court did not abuse its
    discretion by excluding the expert’s testimony for being unreliable. 
    Id. We have
    here a similar set of circumstances, and thus we reach a similar
    conclusion. Like the expert in Frazier, Burton asserts that he relied on the
    evidence in the case, his experience, and relevant literature. He explained in his
    report that he reached his conclusion based on the scientific method, without
    further explaining how he tested his hypothesis to support his conclusions. During
    his deposition, he explained a bit more—declaring that the amount of intrusion and
    the velocity of the adjacent door were the most important factors to his
    24
    Case: 13-10922        Date Filed: 09/12/2014        Page: 25 of 31
    evaluation 11—but even then, his explanation went no further. He did not explain
    how those two variables were relevant, nor did he explain how he used those
    factors to reach his conclusion.
    11
    The parties devote considerable attention in their briefs to the significance, or lack
    thereof, of Cunningham’s calculation of lateral delta-v. We decline to address the point, in part
    because we need not do so to resolve this appeal, but also because the attorneys in this case
    appear to conflate multiple measurements to make their arguments.
    As alluded to earlier, Burton calculated the interior velocity of the adjacent door based on
    the actual velocity of the Mack truck at the time of impact, which he assumed to be 12 mph.
    Cunningham estimated the Mack truck’s velocity to be somewhere between 10 and 24 mph at
    impact. But Cunningham also calculated lateral delta-v as 37 mph. While Hughes claims this
    number is hypothetical, it is based on trigonometry. See supra note 6. When Kia asked Burton
    during his deposition to assume that the lateral delta-v was 37 mph, this assumption was based
    on evidence that could have, and likely would have, been established at trial.
    Burton then testified that if the Mack truck were traveling at 37 mph when it impacted the
    Optima, the interior velocity of the adjacent door would be at least 35 mph. But there is no
    evidence in the record to assume that the Mack truck was traveling at 37 mph when it impacted
    the Optima. Cunningham never retreated from his estimate that the Mack truck was traveling
    between 10 and 24 mph at impact; his calculation of lateral delta-v is an entirely different
    measurement.
    To be sure, Burton agreed with Kia’s attorney that a lateral delta-v of 37 mph would
    mean the interior velocity of the adjacent door was at least 35 mph. But Burton never equated
    the Mack truck’s velocity to lateral delta-v, and he never expressly based the interior velocity on
    lateral delta-v. In short, Burton appears not to have recognized that Kia’s attorney asked about
    interior velocity using a different measurement, lateral delta-v, instead of velocity of the Mack
    truck.
    However, Burton never indicated that he made a mistake when he said a 37 mph lateral
    delta-v would lead to an interior velocity of at least 35 mph, and Hughes’s attorneys have not
    made any argument about the apparent discrepancy we describe here. Thus, we cannot say for
    sure that Burton misspoke. And we would therefore be left to accept Burton’s testimony that a
    37 mph lateral delta-v would lead to an interior velocity of at least 35 mph, which means that
    Burton did not employ his stated methodology—relying on intrusion and interior velocity—
    correctly.
    All of this is to say that we cannot conclude that the District Court committed clear error
    by relying on Burton’s admission, even though it appears to be based on a faulty assumption.
    25
    Case: 13-10922       Date Filed: 09/12/2014      Page: 26 of 31
    Moreover, Burton was unable to rule out the Mack truck impact as the cause
    of Allene’s fatal injury. He admitted that he lacked sufficient information about
    the Optima’s impacts with the Toyota Corolla and Geo Tracker to determine
    whether these impacts caused or did not cause the injury. And although he
    concluded that the impacts with the curbs had the potential to cause Allene to
    impact a structure inside the car and thereby cause her fatal injury, he could not
    opine that the curb impacts actually caused a collision with an interior structure
    and the fatal injury. Nor could Burton say that the impact with the house was
    sufficient to cause the fatal injury. Nevertheless, he asserted that Allene would not
    have sustained the fatal injury had the Optima been equipped with a shut-off
    switch.
    “[S]omething doesn’t become scientific knowledge just because it’s uttered
    by a scientist; nor can an expert’s self-serving assertion that his conclusions were
    derived by the scientific method be deemed conclusive.” McDowell v. Brown, 
    392 F.3d 1283
    , 1299 (11th Cir. 2004) (alteration in original) (internal quotation marks
    And thus, based on this factual finding, the court’s legal conclusion—that Burton did not follow
    his methodology and thus his opinion is unreliable—is not clearly erroneous. However, we need
    not rely exclusively on Burton’s statement because we may affirm the District Court on any basis
    supported by the record, Thomas v. Cooper Lighting, Inc., 
    506 F.3d 1361
    , 1364 (11th Cir. 2007),
    and, as described elsewhere, Hughes failed to carry her burden to demonstrate that Burton’s
    testimony was reliable.
    26
    Case: 13-10922     Date Filed: 09/12/2014    Page: 27 of 31
    omitted). “The trial court’s gatekeeping function requires more than simply taking
    the expert’s word for it.” Fed. R. Evid. 702, advisory committee’s note, 2000
    amendment (internal quotation marks omitted). As the Supreme Court explained
    in Joiner,
    Trained experts commonly extrapolate from existing data. But
    nothing in either Daubert or the Federal Rules of Evidence requires a
    district court to admit opinion evidence that is connected to existing
    data only by the ipse dixit of the expert. A court may conclude that
    there is simply too great an analytical gap between the data and the
    opinion 
    proffered. 522 U.S. at 146
    , 118 S. Ct. at 519.
    The decision to exclude expert testimony is committed to the sound
    discretion of the District Court, see 
    Rink, 400 F.3d at 1291
    , and here the court
    reasonably could have questioned the reliability of Burton’s ultimate opinion given
    the vague manner in which Burton described his methodology coupled with his
    inability to express an opinion about how the various impacts would have affected
    Allene. Cf. Kumho Tire 
    Co., 526 U.S. at 155
    , 119 S. Ct. at 1177 (“The court could
    reasonably have wondered about the reliability of a method of visual and tactile
    inspection sufficiently precise to ascertain with some certainty the abuse-related
    significance of minute shoulder/center relative tread wear differences, but
    insufficiently precise to tell with any certainty from the tread wear whether a tire
    had traveled less than 10,000 or more than 50,000 miles.” (internal quotation
    27
    Case: 13-10922     Date Filed: 09/12/2014    Page: 28 of 31
    marks omitted)). “[T]he deference that is the hallmark of abuse-of-discretion
    review requires that we not reverse an evidentiary decision of a district court unless
    the ruling is manifestly erroneous.” 
    Frazier, 387 F.3d at 1258
    (citations omitted)
    (internal quotation marks omitted). Here, the District Court concluded that the
    leap from data to opinion was too great, and therefore excluded Burton’s
    testimony. Because the court properly applied the law and did not make clearly
    erroneous factual findings in reaching its decision to exclude Burton’s opinion, we
    hold that the court did not abuse its discretion in excluding his testimony.
    V.
    Having concluded that the District Court did not abuse its discretion by
    excluding Burton’s testimony, we must consider whether summary judgment was
    proper. When reviewing a district court’s grant of summary judgment, we exercise
    de novo review. Fils v. City of Aventura, 
    647 F.3d 1272
    , 1287 (11th Cir. 2011).
    Summary judgment is appropriate where the moving party—here, Kia—“shows
    that there is no genuine dispute as to any material fact and the movant is entitled to
    judgment as a matter of law.” Fed. R. Civ. P. 56(a). In reviewing the material
    facts, we draw all inferences in favor of the nonmoving party—here, Hughes. 
    Fils, 647 F.3d at 1287
    .
    28
    Case: 13-10922      Date Filed: 09/12/2014      Page: 29 of 31
    In enhanced injury cases such as this one, general principles of causation
    still apply under Tennessee law. 12 That is, “[a]ny claim for ‘enhanced injuries’ is
    nothing more than a claim for injuries that were actually and proximately caused
    by the defective product.” Whitehead v. Toyota Motor Corp., 
    897 S.W.2d 684
    ,
    694 (Tenn. 1995). Thus, Hughes has the burden of proof on causation, which
    means she must present evidence to create a genuine issue of material fact on both
    cause in-fact and proximate causation. Hale v. Ostrow, 
    166 S.W.3d 713
    , 718
    (Tenn. 2005). As the Supreme Court of Tennessee has explained:
    The defendant’s conduct is the cause in fact of the plaintiff’s injury if,
    as a factual matter, it directly contributed to the plaintiff’s injury. In a
    case such as this one, we must ask whether the plaintiff’s injury would
    have happened ‘but for’ the defendants’ act. If not, then the
    defendants’ conduct is a cause in fact of the plaintiff's injury. It is not
    necessary that the defendants’ act be the sole cause of the plaintiff’s
    injury, only that it be a cause.
    
    Id. (citation omitted).
    “[T]he mere occurrence of an injury does not prove
    negligence . . . . Even when it is shown that the defendant breached a duty of care
    owed to the plaintiff, the plaintiff must still establish the requisite causal
    connection between the defendant’s conduct and the plaintiff’s injury.” Kilpatrick
    v. Bryant, 
    868 S.W.2d 594
    , 599 (Tenn. 1993) (citation omitted).
    12
    As previously mentioned, we apply Tennessee law because Georgia applies the choice-
    of-laws rule of lex loci delicti. See supra note 9.
    29
    Case: 13-10922         Date Filed: 09/12/2014     Page: 30 of 31
    In the context of this case, the Optima’s lack of a shut-off switch must have
    been an actual cause of Allene’s enhanced injury—the fatal injury—before we
    consider whether it was also a proximate cause. Thus, the question of actual
    causation depends then on whether Allene sustained her fatal injury as a result of
    the impact with the Mack truck. If Allene sustained her fatal injury from the Mack
    truck impact, then the additional impacts were not a but-for cause of the fatal
    injury. 13 Without Burton’s opinion that the lack of a shut-off switch caused
    Allene’s fatal injury, Hughes has presented no evidence of actual causation. 14 She
    has not shown that the Mack truck impact did not cause Allene’s fatal injury, nor
    has she shown that the lack of a shut-off switch (as opposed to some other cause,
    such as the removed driver’s front airbag) was an actual cause of the fatal injury.
    As such, Kia is entitled to judgment as a matter of law because Hughes failed to
    create a genuine issue of material fact with respect to actual causation.
    13
    As one treatise explains:
    If one of the two fires burns the plaintiff’s property to the ground before the other
    spreads to the scene, the second fire is not a factual cause at all, even though it
    would have burned the plaintiff’s property in the same way. Your acts today
    cannot in any practical sense cause something that happened in 1939, or even
    something that happened one second before you acted.
    Dan B. Dobbs, Paul T. Hayden & Ellen M. Bublick, The Law of Torts § 189 (2d ed. 2011).
    14
    Even with Dr. Burton’s testimony, Hughes would have a problem getting past
    summary judgment because Burton could not exclude the Mack truck impact as a cause of death.
    Moreover, Burton opined to a reasonable degree of medical certainty that a lateral delta-v of 37
    could have caused Allene’s fatal injury. If Allene sustained her fatal injury as a result of the
    Mack truck impact, then the subsequent impacts would not have led to an enhanced injury.
    30
    Case: 13-10922     Date Filed: 09/12/2014   Page: 31 of 31
    VI.
    The District Court did not abuse its discretion in excluding Burton’s
    testimony. Nor did the court err in granting summary judgment for Kia. We
    therefore AFFIRM the court’s judgment.
    SO ORDERED.
    31