                               UNPUBLISHED

                   UNITED STATES COURT OF APPEALS
                       FOR THE FOURTH CIRCUIT


                               No. 08-2141


JAMES PAUL PUGH, III,

                 Plaintiff - Appellee,

           v.

LOUISVILLE LADDER,    INCORPORATED,    f/k/a   Louisville   Ladder
Group, LLC,

                 Defendant – Appellant,

           and

HOME DEPOT U.S.A., INCORPORATED,

                 Defendant.



Appeal from the United States District Court for the Middle
District of North Carolina, at Greensboro.   N. Carlton Tilley,
Jr., Senior District Judge. (1:06-cv-00656-NCT-PTS)


Argued:   September 25, 2009                 Decided:   January 5, 2010


Before MOTZ and AGEE, Circuit Judges, and Mark S. DAVIS, United
States District Judge for the Eastern District of Virginia,
sitting by designation.


Affirmed by unpublished opinion. Judge Davis wrote the opinion,
in which Judge Motz and Judge Agee joined.


ARGUED: James Donald Cowan, Jr., ELLIS & WINTERS, LLP, Cary,
North Carolina, for Appellant.  Vance Barron, Jr., Greensboro,
North Carolina, for Appellee.     ON BRIEF: Andrew Chamberlin,
Dixie T. Wells, ELLIS & WINTERS, LLP, Greensboro, North
Carolina; Paul K. Sun, Jr., ELLIS & WINTERS, LLP, Raleigh, North
Carolina, for Appellant.


Unpublished opinions are not binding precedent in this circuit.




                                2
DAVIS, District Judge:

     In this product liability diversity case, James Paul Pugh,

III (“Pugh”) alleged that a ladder manufactured by Louisville

Ladder,   Inc.,   (“LL”)       structurally     failed    during     normal    use,

causing   Pugh    to    fall    and   suffer    injuries.       At    trial,      two

engineering experts testified on behalf of Pugh and the jury

returned a verdict in Pugh’s favor.             LL filed the instant appeal

arguing   that    the    district     court    abused    its   discretion      with

respect   to   three     evidentiary    rulings.         Finding     no   abuse    of

discretion, we affirm.

                                        I.

                                        A.

     Excluding the few seconds during which Pugh fell from his

ladder, the facts are undisputed.              Pugh purchased an eight-foot

LL ladder from Home Depot in March of 2003.                    The ladder was

manufactured in Mexico in July of 2002 and had a “load capacity”

of 225 pounds.          Pugh read all of the warnings on the ladder

label and the ladder showed no visible signs of damage at the

time of purchase or at the time of use.                  After purchasing the

ladder in March of 2003, Pugh hung it on hooks in his garage

where it remained until July 10, 2003, when he used it for the

first time.

     On July 10, 2003, Pugh placed the ladder on his living room

floor in order to install a skylight shade.                 At the time, Pugh

                                        3
weighed 215 pounds and was carrying less than 10 pounds of tools

while using the ladder.           Pugh went up and down the ladder twice

without incident.         On Pugh’s third trip up the ladder, he fell

while standing on the ladder’s sixth step.                         Pugh has no memory

of the actual fall, but recalls later realizing that he was

lying on the ground.           When Pugh realized that he had fallen, he

was dazed and disoriented and felt pain in his head, neck, and

shoulders.        Pugh   was     taken     to    the       emergency    room       and   was

diagnosed with muscle strain and a concussion.

       After    Pugh’s        fall,     his      ladder          evidenced     extensive

structural damage.        The worst damage was located on each of the

side rails, between the first and second steps on the left rail

and between the second and third steps on the right rail.                            There

were    also    visible        cracks    around           and    through     the    rivets

connecting     the    first    three     steps       to    the   side   rails.       After

Pugh’s ladder was thoroughly photographed and examined, experts

for both parties agreed upon destructive testing to permit more

complete examination.           Upon microscopic examination at 1000x and

2000x    power,       Pugh’s     experts        discovered         “micro-cracks”         at

locations throughout the ladder, including at step seven, above

the step being used by Pugh when the accident occurred.

       The primary issue at trial was the manner in which Pugh’s

accident occurred.            Pugh’s theory was that his ladder had a

manufacturing        defect    consisting       of    microscopic       cracks      at   the

                                           4
ladder’s         rivets    and    that,    during         normal   use,     such    cracks

propagated          into         larger        cracks         causing       catastrophic

failure/buckling that resulted in Pugh’s fall.                             In contrast,

LL’s theory was that the ladder was not defective and did not

fail,      but    that    Pugh    tipped       the    ladder    during     use     and   the

ladder’s     post-accident         severely         damaged    condition     was    caused

during the accident when Pugh’s body fell onto the ladder.

                                               B.

        Pugh filed the instant products liability action in North

Carolina state court against LL and Home Depot.                           The defendants

removed the action to the United States District Court for the

Middle District of North Carolina.                        Both defendants moved for

summary judgment, which was granted with respect to Home Depot

but denied with respect to LL.                       Prior to trial, LL moved to

exclude both of Pugh’s proposed expert witnesses.

        On April 28, 2008, the day before trial, the district court

conducted a lengthy pre-trial motions hearing, and the majority

of   the    hearing       was    spent    on    LL’s      motion   to   exclude     Pugh’s

proposed experts: Dr. Ajit Kelkar (“Dr. Kelkar”) and Dr. William

Craft    (“Dr.      Craft”),      professors         of   mechanical    engineering      at

North Carolina A&T State University.                      At the pre-trial hearing,

the court heard testimony from both Drs. Kelkar and Craft as

well as LL’s expert.             LL conceded that Drs. Kelkar and Craft had



                                               5
the education and expertise to testify on the subject at issue

but challenged the reliability of their opinions.

       At the conclusion of the pre-trial hearing, the district

court denied LL’s motion to exclude Pugh’s experts.                                       Although

Drs.       Kelkar    and       Craft    were    permitted         to      testify,       the   court

granted       a   motion        in     limine    filed      by       LL   restricting          Pugh’s

experts from testifying about testing performed on an “exemplar

ladder” with the same LL model number as the accident ladder.

The     court        excluded          such     testimony            because       the    evidence

established that LL had sold two differently designed ladders

under this one model number.                        Because the accident ladder and

the exemplar ladder had a different design, comparison of the

specifications            of    one     to    the       other    was      deemed    to    have    no

relevance. 1

       At    trial,       Dr.    Kelkar       testified         at     length   during         Pugh’s

case-in-chief regarding his theory of crack propagation leading

to the catastrophic structural failure of Pugh’s ladder.                                         Dr.

Craft       did     not    testify       during         Pugh’s       case-in-chief        but    was

       1
       Pugh’s experts were unable to purchase a ladder with the
same LL model number as the accident ladder since it was
apparently no longer being sold in stores at the time of the
lawsuit. By happenstance, Dr. Kelkar located a ladder with the
same LL model number as the accident ladder at his Temple.
Pugh’s experts conducted testing on such ladder and discovered
that its rails were thicker than the accident ladder. However,
the variation in thickness was not indicative of a defect in the
accident ladder due to the variation in designs.



                                                    6
reserved as a rebuttal witness.                      LL objected to Pugh’s decision

to    reserve    Dr.       Craft,    but   the       district     court     overruled           such

objection.

       During    LL’s        presentation        of     its     case,      defense     counsel

attempted to introduce evidence to establish the absence of end-

user complaints reporting “cracks” on LL ladders with the same

model number as the accident ladder.                            Pugh objected to such

proposed    evidence         on     hearsay     grounds        and,    following       a    bench

conference, the district court excluded such testimony based on

its unreliability.

       At the conclusion of the case, the jury returned a verdict

in Pugh’s favor.             LL filed the instant appeal challenging: (1)

the    denial    of    LL’s       motion   to        exclude    the    testimony       of       Drs.

Kelkar and Craft; (2) the exclusion of testimony regarding the

absence    of     end-user          complaints         reporting       “cracking”          of    LL

ladders with the same model number as Pugh’s ladder; and (3) the

ruling    permitting          Dr.    Craft      to     be   reserved        as    a   rebuttal

witness.        LL argues that the cumulative effect of the above

stated errors denied LL a fair trial.



                                              II.

       District       courts       have    broad       latitude       in   determining          the

admissibility         of    evidence,      and       evidentiary       rulings,       including

Daubert    rulings,         will     not   be    overturned        absent        an   abuse       of

                                                 7
discretion.     Bryte ex rel. Bryte v. American Household, Inc.,

429 F.3d 469, 475 (4th Cir. 2005).           “A district court abuses its

discretion when it acts arbitrarily or irrationally, fails to

consider judicially recognized factors constraining its exercise

of discretion, relies on erroneous factual or legal premises, or

commits an error of law.”        United States v. Delfino, 510 F.3d

468, 470 (4th Cir. 2007).       However, even if the district court

abuses its discretion, such evidentiary ruling “is reversible

only if it affects a party’s substantial rights.”                 Schultz v.

Capital Int’l Sec., Inc., 466 F.3d 298, 310 (4th Cir. 2006); see

Fed. R. Evid. 103(a).

                                   A.

     Federal Rule of Evidence (FRE) 702 acts as the guidepost

for the admissibility of expert testimony.                United States v.

Wilson,   484   F.3d   267,   274-75       (4th   Cir.   2007).    The   rule

provides:

     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, if (1)
     the testimony is based upon sufficient facts or data,
     (2)   the   testimony   is    the   product  of   reliable
     principles and methods, and (3) the witness has
     applied the principles and methods reliably to the
     facts of the case.

Fed. R. Evid. 702.      In considering the admissibility of expert

testimony, a district court acts as a gatekeeper and must assess

                                       8
whether    an    expert’s        proffered         testimony      is   both     sufficiently

reliable and relevant.                 Kumho Tire Co. v. Carmichael, 526 U.S.

137, 141 (1999); United States v. Moreland, 437 F.3d 424, 431

(4th    Cir.     2006).          The    relevance          and   reliability      of    expert

testimony       is   examined          through         consideration     of,    among    other

things: “(1) whether the particular scientific theory ‘can be

(and    has     been)      tested’;          (2)   whether       the   theory    ‘has     been

subjected to peer review and publication’; (3) the ‘known or

potential rate of error’; (4) the ‘existence and maintenance of

standards       controlling            the     technique's        operation’;      and     (5)

whether the technique has achieved ‘general acceptance’ in the

relevant      scientific         or    expert      community.”         United     States    v.

Crisp, 324 F.3d 261, 266 (4th Cir. 2003) (quoting Daubert v.

Merrell Dow Pharms., Inc., 509 U.S. 579, 593-94 (1993)).

        Although reliability of an expert’s principles and methods,

as well as the application of the facts to such methods, must be

examined by the district court, the court “need not determine

that the proffered expert testimony is irrefutable or certainly

correct,” since, like all forms of testimony, “expert testimony

is     subject       to     testing          by        ‘[v]igorous     cross-examination,

presentation of contrary evidence, and careful instruction on

the burden of proof.’”                   Moreland, 437 F.3d at 431 (4th Cir.

2006)     (quoting        Daubert,           509    U.S.    at    596)      (alteration     in

original);       see      also    Maryland         Casualty      Co.   v.    Therm-O-Disc.,

                                                   9
Inc., 137 F.3d 780, 784 (4th Cir. 1998) (noting that “[a]ll

Daubert demands            is   that     the    trial      judge      make    a    ‘preliminary

assessment’” of whether the proffered testimony is both reliable

and     helpful).             Neither    FRE     702      nor    case      law     establish    a

mechanistic test for determining the reliability of an expert’s

proffered testimony; on the contrary, “‘the test of reliability

is flexible’ and ‘the law grants a district court the same broad

latitude         when    it    decides    how    to    determine        reliability      as    it

enjoys in respect to its ultimate reliability determination.’”

Wilson, 484 F.3d at 274 (quoting Kumho Tire Co., 526 U.S. at

141-42) (second emphasis added). 2                    Although the district court is

afforded broad latitude in performing such flexible inquiry, the

focus       of    the     inquiry       should       be    on    the       “‘principles        and

methodology’            employed   by    the     expert,        not   on     the    conclusions

reached.”         Moreland, 437 F.3d at 431 (quoting Daubert, 509 U.S.

at 594-95) (emphasis added).

        2
       As recognized in Wilson, a district court’s reliability
determination “does not exist in a vacuum,” and there are
“meaningful differences in how reliability must be examined with
respect to expert testimony that is primarily experiential in
nature as opposed to scientific.”     Wilson, 484 F.3d at 274.
Here, it appears that some of Pugh’s experts’ testimony was
based on post-accident testing and some was “experiential in
nature.”   For example, Dr. Kelkar testified that, based on his
years of experience working with NASA, numerous branches of the
military, and several private companies, he knows that punching
a hole in any metal in order to install a rivet weakens the
metal and that crack propagation from rivets in metals is a
widely accepted phenomenon.


                                                10
       Here,    LL    argues       both      that   the      district      court    failed   to

properly perform its role as gatekeeper and that the testimony

of Pugh’s experts was not based on sufficient facts or data.

The latter of these arguments focuses on the contention that

Pugh’s experts failed to apply their “principles and methods

reliably to the facts of the case.”                      Fed. R. Evid. 702(3).

                                               1.

       The Court first considers LL’s contention that the district

court did not properly perform its role as gatekeeper because

the court purportedly shifted the expert admissibility burden to

LL.    We begin consideration of this argument by noting that the

proponent      of     expert       testimony        does     not    have    the    burden    to

“prove”    anything,         but      must    “come     forward      with    evidence       from

which the court can determine that the proffered testimony is

properly admissible.”              Maryland Casualty, 137 F.3d at 784.

       LL’s burden argument ignores the context of its challenge

to    Pugh’s    experts         and     is   only     supported      by     the    record    if

excerpts       from       the     lengthy      Daubert        hearing       are    viewed     in

isolation.          LL began its argument at the Daubert hearing by

acknowledging the “many articulations” of the Daubert standard

and clarifying that the burden to establish the admissibility of

expert    testimony         was    on     Pugh.         LL   then    argued       that   expert

testimony should not be admitted if it is based on “assumptions

or    beliefs,       if    the     witness        has      failed    to     consider      other

                                               11
explanations, or if the witness’s theory is easily falsifiable

with a single counter example.”              (J.A. 452.)       LL stated that the

reason the testimony should be excluded in this case is that

“[w]e    have   a    failure   to    test.        We   have    opinions    based    on

assumptions.        We have failure to consider other explanations,

and we have an easily falsifiable theory . . . .”                     (Id.)       LL’s

subsequent argument did not focus on attacking the “principles

and methodology” employed by Pugh’s experts, but instead focused

on    why    their     conclusions         were    incorrect,       i.e.    “easily

falsifiable.”

      During LL’s counsel’s summary of why principles of physics

would disprove Pugh’s experts’ theory, the court interjected,

stating:    “You’re     saying      it’s   physically        impossible    [for    the

buckling] to happen like [Pugh’s experts opine]?” (Id. at 457.)

Counsel responded: “It is.           Jumping ahead, Your Honor, it didn’t

happen like that.”         (Id.)      After the court confirmed that LL’s

“impossibility” claim was being advanced in an effort to exclude

the     testimony     of   Pugh’s      experts,        the    following    exchange

occurred:

 LL Counsel: Your Honor, I’m careful to point out, that
             the burden on the Plaintiff is to prove by a
             preponderance of the evidence, that the
             testimony is reliable and that the testimony
             has employed reliable scientific methodology.
 Court:      They don’t have to prove the opinion is
             reliable.
 LL Counsel: They have to prove the reliability of the
             method and contrary wise it’s not the

                                           12
                 Defendant’s burden to prove that the opinion
                 is impossible.
 Court:          Well, if you want to exclude it, it seems to
                 me, that you need to show me scientifically,
                 why that is physically impossible or highly
                 unlikely, because if they applied proper
                 methodology, and their opinion is wrong,
                 isn’t that for the finder of fact to
                 determine?

(J.A. 457-58) (emphasis added).                LL highlights this statement by

the district court, among others, in an effort to establish that

the court improperly shifted the burden to LL and/or improperly

applied an “impossibility” standard.

      After    considering    the    Daubert       hearing       transcript     in    its

entirety, we find that LL fails to establish that the district

court     erroneously   shifted     the    burden      of   production     to    LL   or

otherwise failed to exercise its role as gatekeeper. 3                        Although

LL    had     referenced     purported          errors      in    Pugh’s      experts’

methodology prior to the above quoted exchange, LL’s argument

had   focused    almost    entirely       on     the     contention    that     Pugh’s


      3
       Although LL’s claims of error before this court focus
solely on the Daubert hearing, we recognize that the district
court   had  additional   evidence  before  it   supporting  the
admissibility of Pugh’s experts’ testimony, such as a joint
affidavit submitted by Drs. Kelkar and Craft with numerous
exhibits including engineering formulas, published articles, and
“expert reports” detailing the testing Drs. Kelkar and Craft
performed in this case.    The fact that the district court had
such materials prior to the Daubert hearing further explains the
manner in which the hearing was conducted, i.e. LL was given an
opportunity to attack Pugh’s prior assertions in support of the
admissibility of his experts.



                                          13
experts’    conclusions      were       readily    falsifiable.        The   district

court’s statement regarding impossibility/unlikelihood, taken in

context, appears to be a response to such repeated attacks on

Pugh’s experts’ conclusions.              Furthermore, a careful examination

of   the    statement     made     by    the    district     court   regarding     the

correctness of an expert’s conclusions reveals that the court

was following this Court’s instruction to focus on the experts’

“principles and methodology” and not on the conclusions reached.

Moreland, 437 F.3d at 431. 4            Tellingly, the court’s statement was

limited to a situation where a challenged expert had applied

“proper methodology.”

      Further supporting the above finding, prior to the lunch

recess     from    the   lengthy    Daubert       hearing,     the   district   court

attempted     to    redirect     LL’s     focus    for   the    remainder     of   the

hearing, stating that counsel was continuing to argue that it

      4
        The Supreme Court has recognized that “conclusions and
methodology are not entirely distinct from one another” and that
“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.” General Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997).
Such holding, however, does not shift the focus of the Daubert
test to experts’ conclusions, but merely clarifies that the
district court’s broad discretion includes the discretion to
find that there is “simply too great an analytical gap between
the data and the opinion proffered.”   Id.   Our recent decision
in Moreland, decided after Joiner and the 2000 amendments to
Rule 702, reiterates the fact that the proper focus remains on
the expert’s “principles and methodologies.” Moreland, 437 F.3d
at 431.



                                           14
was “scientifically impossible” for the ladder to fail in the

manner claimed by Pugh’s experts and that the focus should be on

the validity of the scientific methods utilized and not on the

weight of such testimony — which is a question for the jury.

(J.A. 552-53.)       After the lunch recess, the court again repeated

its concern, stating:

      But now share with me, if you would, [counsel], where
      you are with regard to scientific methodology.      It
      sounds to me like what you are doing is cross-
      examination with regard to the weight of [Pugh’s
      expert’s] opinion, and not the validity of his opinion
      and, you know, this is not a free deposition or free
      opportunity for cross-examination.

(J.A. 592-93.)       After a brief exchange that concluded with LL’s

counsel’s offer to end his questioning the court responded: “If

you   have   other    questions   that    go   to   the   methodology,   you

certainly should ask them . . . .”        (Id. at 594.)

      We therefore find that the district court did not impose an

improper burden on LL nor otherwise abuse its discretion in the

manner in which it conducted the Daubert hearing.              See Maryland

Casualty, 137 F.3d at 784 (declining to reverse the district

court’s   Daubert     ruling   notwithstanding      the   court’s   incorrect

statement regarding the burden, made at the beginning of the

Daubert hearing, because “the general process contemplated by

Daubert took place in the hearing and . . . [the plaintiff]

squarely bore the burden of production”).



                                     15
                                          2.

      LL    next     argues       that     even       if      the   district        court

appropriately performed its role as gatekeeper, Pugh’s experts

should not have been permitted to testify because they failed to

apply their “principles and methods reliably to the facts of the

case.”      Fed.     R.   Evid.     702(3).           We    acknowledge     that     such

contention presents a close question.                      However, on such a close

discretionary ruling we may not substitute our judgment for that

of the district court.             United States v. MacDonald, 688 F.2d

224, 228 (4th Cir. 1982).

      Although      Pugh’s    experts’        initial        conclusion,     that     the

ladder     failed    structurally,        was     based       solely   on    a     visual

inspection of the post-accident ladder, such experts thereafter

performed    several      tests   to     support      their    initial      assessment.

These tests included: (1) testing to rule out a design defect; 5

(2)   “non-destructive”       testing,        including       labeling,     measuring,

and photographing the accident ladder; 6 (3) destructive testing,

whereby    samples     were   cut      from     the    ladder’s     side     rails    and



      5
       Pugh’s experts freely admitted that the accident ladder’s
design was more than sufficient to support its rated 225 pounds.
      6
       Visible cracks were apparent             on the edge of the rivets and
were fully propagated through the                flange of the side rails in
the area where the ladder was                   deformed and Pugh’s experts
testified that the paths of such                 cracks were consistent with
structural failure.



                                          16
submitted       for     testing    to      a     third-party       facility;    (4)

fractographic examination of the side rails and rivets using a

high magnification optical microscope and a scanning electron

microscope; 7     (5)     using   “standard        engineering      formulas”    to

determine that fully propagated cracks would have resulted in a

substantial reduction of the “moment of inertia” of the side

rails, which would in turn decrease the rails’ load capacity;

and (6) testing C-shaped sections of aluminum designed to mimic

the accident ladder’s side rails whereby mock rivet holes were

drilled, cracks simulated, and the reduced load capacity tested

-   such   testing      was   videotaped       which   permitted    peer   review. 8


      7
        Dr. Kelkar represented that this was a standard
engineering   technique   to    identify  pre-failure   fracture
mechanisms, and Dr. Kelkar’s qualification in the field of
fracture mechanics went unchallenged by LL. (J.A. 364-65.) In
1985 Dr. Kelkar obtained his Ph.D. devoted entirely to fracture
mechanics, particularly in the area of failures due to fractures
that can be caused by impact.     (Id. at 508.)  Dr. Kelkar has
worked for NASA, the Air Force, Army, and Navy, and authored
over 200 publications.    He has also worked on several rivet
studies and is an engineer for a school bus company for which he
helped develop a new design aimed at eliminating cracks in
manufacturing due to the riveting process. (Id. 507-10.)
      8
       According to engineering publications cited by Pugh’s
experts, (J.A. 364), a hole in a structure acts as a “stress
riser”   and  cracks   initiate  at   points   of  high   stress
concentration, such as rivets. Pugh’s experts’ testing revealed
that micro-cracks existed around the rivet holes on the upper
side rails of the accident ladder above the step where a load
had been placed on the ladder by Pugh. Pugh’s experts contended
that cracks at this location supported their hypothesis that the
cracks pre-dated the accident since weight applied below such
step would not cause such cracks. LL’s counsel failed to impugn
(Continued)
                                        17
Based both on their experience and the testing outlined above,

Pugh’s experts determined that their structural failure theory

was scientifically supported by the facts of this case and the

most likely cause of the accident.

       In addition to testing and analysis supporting their crack

propagation    theory,       Pugh’s     experts        performed        testing    and

analysis to disprove the opposing theory – impact damage.                         Based

on their experience, Pugh’s experts testified at the Daubert

hearing that a blunt object, like a human’s upper torso, falling

onto an aluminum ladder could not create the buckling damage

readily observable on the accident ladder.                    See Kumho Tire Co.,

526 U.S. at 156 (“[N]o one denies that an expert might draw a

conclusion from a set of observations based on extensive and

specialized   experience.”).          To     prove     such    conclusion    through

testing, Pugh’s experts conducted impact testing by dropping a

mass   weighing     240   pounds,     roughly     in    the     human   form,     on   a

similar 6 foot aluminum ladder.              Such impact testing, which was

videotaped    and     thus    subject        to   peer        review,    purportedly

established   that    the    damage    apparent        on   the   accident      ladder

could not have been caused by a person falling onto the ladder.

Cf. Oglesby v. General Motors Corp., 190 F.3d 244, 250 (4th Cir.



Pugh’s expert’s reliance on such cited sources at the Daubert
hearing.



                                        18
1999)    (recognizing     deficiencies       in   the    plaintiff’s       expert’s

testing/analysis     including   the     expert’s       failure      to   “eliminate

other equally plausible causes” for the failure of the component

in question).

     Notwithstanding      the   tests    outlined       above,    LL      highlights

several alleged deficiencies with Pugh’s experts’ conclusions,

including the experts’ failure to investigate the manufacturing

process,   failure   to    analyze     the   likelihood       that    micro-cracks

would propagate based on aluminum’s physical properties, failure

to perform computer modeling, failure to definitively establish

whether the micro-cracks pre-dated the accident, and failure to

advance    direct     proof     that     micro-cracks         occurred       during

manufacturing. 9     However,    in     light     of    the   testing      that   was

performed to both support Pugh’s hypothesis and discredit LL’s


     9
       Pugh’s experts consistently reported that due to the
accident ladder’s severely damaged state it was impossible to
conclusively determine the precise manner in which it failed,
but that the testing performed to support their theory and rule
out LL’s theory established that their theory was the most
probable scientific explanation.   We are unpersuaded by LL’s
contention that Dr. Craft admitted that tests could have been
performed to establish whether any cracks pre-dated the
accident.   Dr. Kelkar stated that “for this particular ladder”
he could not “metallurgically or microscopically” put a date on
the cracks. (J.A. 546.) Dr. Craft’s later statement, that “it
might be possible under certain conditions” to date a crack
based on chemical or dirt infiltration, merely acknowledges the
possibility of such testing under hypothetical facts and does
not appear to be a concession that such tests were viable on
these facts. (J.A. 596-97.)



                                       19
hypothesis, and the lack of evidence suggesting that any of such

testing was unreliable, the alleged failure of Pugh’s experts to

perform additional testing goes more to the weight of the expert

testimony than to its Daubert admissibility.               See Westberry v.

Gislaved Gummi AB, 178 F.3d 257, 265 (4th Cir. 1999) (indicating

that alternative causes for a medical diagnosis advanced by a

defendant go to the weight of a medical expert’s opinion, not

its   admissibility,      as   long   as   the    plaintiff’s    expert   took

“serious account of other potential causes” in formulating a

diagnosis); Schmude v. Tricam Indus., 556 F.3d 624, 625-26 (7th

Cir. 2009) (rejecting the defendant’s claim of error regarding

the   plaintiff’s     expert’s    failure        to   perform   testing   that

replicated a ladder’s collapse and noting that the defendant

failed to establish what kind of test would prove whether the

hypothesized cause for the collapse was correct).

      LL therefore fails to establish that the testing outlined

above,     along   with   “experiential”     testimony     offered   by   Drs.

Kelkar and Craft, was not sufficiently relevant, reliable, and

based on the facts of this case. 10              Accordingly, we decline to

disturb the district court’s determination, made after a lengthy

      10
        In explaining its Daubert ruling, the district court
expressly referenced Pugh’s experts’ experiential testimony,
their testing in support of Pugh’s theory, and their explanation
as to why impact damage was not supported by the facts of this
case. (J.A. 610-11.)



                                      20
Daubert hearing, that Pugh’s experts were permitted to present

their opinions to the jury where the weight of such opinions

would      be     tested     though      “‘[v]igorous          cross-examination,

presentation of contrary evidence, and careful instruction on

the   burden     of    proof.’”      Moreland,   437    F.3d    at   431   (quoting

Daubert, 509 U.S. at 596).

                                         B.

      LL next challenges the district court’s ruling excluding

testimony regarding the absence of end-user complaints reporting

“cracking” of LL ladders with the same model number as Pugh’s

ladder.     At trial, a LL safety engineer testified that LL had a

system in place for documenting and tracking incidents/accidents

reported    to    LL    by   end    users.      After   establishing       that    LL

recorded    all       customer     complaints    and    criticisms     about      its

ladders, the following exchange occurred:

 LL Counsel:   Now, before Mr. Pugh came along with this
               particular claim in the 85,000 ladders that
               you sold of this model, did anyone make any
               kind of claim that the ladder they purchased
               had cracked and was just unable to hold a
               user’s weight?
 Pugh Counsel: Objection.
 Court:        In that fashion, yes.
 LL Counsel:   Did anybody claim that their L2211-08S had
               cracks in it?
 Pugh Counsel: Objection.
 Court:        Approach the bench.

(J.A. 1418) (emphasis added).




                                         21
      During       the    bench       conference,       Pugh    immediately        indicated

that his objection was based on hearsay.                        LL responded by citing

the hearsay exception set forth in FRE 803(7).                            Such rule states

that the following evidence is not excluded by the hearsay rule:

      Evidence that a matter is not included in the
      memoranda reports, records, or data compilations, in
      any form, kept in accordance with the provisions of
      [the   business  records   exception  set   forth  in]
      paragraph   (6),   to   prove  the   nonoccurrence  or
      nonexistence of the matter, if the matter was of a
      kind of which a memorandum, report, record, or data
      compilation was regularly made and preserved, unless
      the sources of information or other circumstances
      indicate lack of trustworthiness.

Fed. R. Evid. 803(7).

      After        hearing         from     both     parties,       the   district        court

sustained Pugh’s objection to the specific “cracking” question

posed, not because LL’s business records were deemed to fall

outside      of    FRE    803,        but   because     the     court     found    that     the

proffered testimony had “no reliability” based on the phrasing

of   the    question          asked    to     the    witness.        (J.A.      1439.)      The

challenged         question           asked     whether        LL    received       customer

complaints        about       LL   ladders      that    “had    cracked.”         The    court

concluded         that    a    lay     person        would    simply      not    identify    a

structural failure, resulting in a post-accident ladder in a

similar condition to Pugh’s ladder, as a “cracking” failure.

      Applying the deferential abuse of discretion standard, we

again      conclude      that      overturning         the   district      court’s       ruling


                                                22
would invade the broad discretion afforded the district court

and require this court to substitute its judgment for that of

the district judge.          FRE 803(7) permits the introduction of the

absence of a business record to prove the nonoccurrence of an

event “unless the sources of information or other circumstances

indicate     lack    of     trustworthiness.”           Fed.     R.     Evid.    803(7)

(emphasis     added).        While    the   district      court       used     the   word

“reliability” and not “trustworthiness,” the court’s rationale

for excluding the testimony was not an abuse of discretion as

the district court provided adequate justification for finding

that    “other   circumstances”         rendered    the    proffered          testimony

untrustworthy.

       Alternatively, even if we found that “unreliability” was an

insufficient basis to exclude testimony reporting the lack of

“cracking” complaints, a separate ruling made by the district

court provides an independent basis for the exclusion of such

testimony. 11       After    the     district   court     made    the        reliability

ruling      discussed     above,     the    court   excluded          LL’s    proffered

testimony     regarding      six   customer     complaints       it    received      that

were unrelated to “cracking.”              The court excluded such testimony

regarding these “non-cracking” complaints because LL failed to


       11
       Such independent basis for excluding testimony discussing
the lack of “cracking” complaints is unchallenged on appeal.



                                           23
produce/introduce          as   a   trial        exhibit     the    business    records

documenting      such   complaints.          The     court    explained      that     such

testimony would not be permitted in the absence of the documents

because opposing counsel cannot counter testimony regarding the

contents of documents he has never seen.                      Although the district

court’s analysis supporting such ruling focused on the exclusion

of the six complaints LL actually received, the ruling is broad

enough to act as an alternative justification to bar testimony

about     the    cracking       complaints         that     were    purportedly       not

received.       To clarify, if the failure to produce/introduce the

pertinent       business    records       barred     testimony       about     what   the

business    records     actually      stated,       it     surely   barred     testimony

about what the same records did not state since the only way to

prove    the    negative—no     cracking         complaints—is      to   consider      the

contents of the complaints actually received.                       Accordingly, LL’s

failure     to     introduce        its     business        records      provides       an

independent justification for excluding testimony discussing the

lack of “cracking” complaints.

                                            C.

        LL’s third evidentiary challenge contends that the district

court erred by permitting Pugh’s second expert, Dr. Craft, to be

reserved as a rebuttal witness.                   FRE 611(a) states that “[t]he

court shall exercise reasonable control over the mode and order

of interrogating witnesses and presenting evidence so as to (1)

                                            24
make    the     interrogation           and   presentation        effective          for    the

ascertainment of the truth, (2) avoid needless consumption of

time,     and   (3)     protect         witnesses       from    harassment       or        undue

embarrassment.”          Fed.      R.    Evid.      611(a).       Notwithstanding           the

court’s       discretion      regarding          witness       order,    “[o]rdinarily,

rebuttal evidence may be introduced only to counter new facts

presented in the defendant’s case in chief.”                            Allen v. Prince

George's County, Md., 737 F.2d 1299, 1305 (4th Cir. 1984).

       Here, prior to resting, Pugh’s counsel informed the court

that Pugh intended to reserve Dr. Craft for rebuttal in order to

speed along the presentation of the evidence.                           No objection to

such    proposal       was    initially          made     by     LL.         (J.A.     1083.)

Thereafter,      LL    objected         to    the    reservation        of     Dr.     Craft,

contending that a rebuttal witness should only be allowed to

testify as to “things that are surprise or unexpected . . . .”

(Id. at 1155-56.)            The district court made no immediate ruling

on such objection, but later overruled the objection, indicating

that rebuttal would not be limited to surprise evidence.                                   (Id.

at 1302.)

       Prior to Dr. Craft’s testimony, the district court again

allowed LL to argue against the reservation of Dr. Craft.                                    The

court, having reviewed the case law cited by LL, reaffirmed its

earlier       ruling    and     indicated          that    rebuttal      testimony           was

appropriate      as    long   as    it    “clarifies,          rebuts   or    explains       or

                                              25
disproves or goes to disproving or explaining [or] clarifying

the testimony of [LL’s witnesses].”                       (Id. at 1399.)            The court

rejected        LL’s    contention          that      Dr.     Kelkar          already     fully

challenged LL’s expert’s position during Pugh’s case-in-chief,

indicating that a plaintiff’s expert “can only anticipate so

much of what the defense evidence is going to be . . . .”                                  (Id.

at 1399-400.)

      After reviewing the trial transcript, we find that LL fails

to establish that the district court abused its broad discretion

in exercising control over the “mode and order of interrogating

witnesses.”        Fed. R. Evid. 611(a).                  LL fails to establish that

precedent        requires      a     district      court      to   limit        rebuttal     to

surprise evidence – the fact that we have previously held it

within      a   district      court’s       discretion        to       limit    rebuttal     to

surprise        evidence      does    not    equate        with    a    requirement        that

rebuttal must always be limited in such manner.                                 See Hospital

Bldg. Co. v. Trustees of Rex Hosp., 791 F.2d 288, 294 (4th Cir.

1986) (finding no abuse of discretion under the circumstances

where the district court limited rebuttal to surprise evidence

in light of the fact that plaintiff took ten weeks to present

its case-in-chief).            The Court’s decision in Allen, relied on by

LL,   is    likewise       distinguishable           from    the   instant         case   since

Allen      involved    the     rejection        of    the    plaintiff’s           attempt   to

introduce       new    data    on     rebuttal       in     support      of    a   new    trial

                                             26
strategy not pursued as part of the plaintiff’s case-in-chief.

Allen, 737 F.2d at 1305.               On the facts before this Court, the

district    court    did   not    abuse      its     discretion     by    declining    to

limit     rebuttal    evidence         to   a      response    to    LL’s     “surprise”

testimony, nor did the district court abuse its discretion in

permitting Dr. Craft to testify for the first time on rebuttal. 12



                                            III.

     We    conclude    that      the    district       court   did    not     abuse    its

discretion with respect to any of the challenged evidentiary

rulings.      Finding      no    abuse       of     discretion,      we     reject    LL’s



     12
        LL also appears to argue, primarily in its reply brief,
that Dr. Craft’s actual testimony was improper because it was
non-responsive to LL’s evidence and was merely rehashing what
should have been previously presented.    However, such objection
was not preserved below. In rejecting LL’s preemptive challenge
to the reservation of Dr. Craft, the district court expressly
invited LL’s counsel to object during Dr. Craft’s testimony if
Dr. Craft started to “rehash what could have been said earlier .
. . .”     (Id. at 1399.)    A review of Dr. Craft’s testimony
reveals that LL’s counsel did not once object to the scope of
the inquiry during Dr. Craft’s testimony. (Id. at 1525-61.) We
therefore do not find any error regarding the “responsiveness”
of the testimony actually elicited as the district court was
never presented an objection once the scope of Dr. Craft’s
testimony became clear.    See United States v. Smith, 452 F.3d
323, 330 (4th Cir. 2006) (recognizing that although motions in
limine often suffice to preserve objections for appeal, such is
not the case when “the exact nature” of the error complained of
cannot be known at the time the motion is decided); United
States v. Williams, 81 F.3d 1321, 1325 (4th Cir. 1996) (finding
a motion in limine insufficient to preserve an objection when
the motion was not based on the “precise issue” later raised).


                                             27
argument    regarding   the   “cumulative   effect”   of   the   alleged

errors.    Accordingly, we affirm.

                                                                 AFFIRMED




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