In the case of Mark Jones v Harley-Davidson (2016 U.S. Dist. LEXIS 48060 ), the present motion to exclude expert witness of the defendant arises out of a suit for damages involving a motorcycle accident. The plaintiff filed this motion seeking to dismiss the expert testimony of David Thom, who was introduced as an expert by the defendant to opine on the injuries caused to the plaintiffs in this case. The defendant had alleged that the expert’s testimony on injuries caused was neither relevant nor reliable and should be excluded under Rule 702 of the Federal Rules of Evidence. The Court analysed these claims and found that the defendant’s claims attacked the weight rather than the admissibility of the expert testimony. Thus the Court only excluded that part of Mr. Thom’s testimony which was deemed to be beyond his qualifications to opine on.


The dispute in this case arose from a certain motorcycle accident that the plaintiff suffered. The main discussion in this case centered around the aspects of reliability and relevance that form the central part of the Daubert test. There was also an ancillary question on qualification of the expert. The Court analysed the challenge in context of the gatekeeping role of the court as laid down in the Daubert test as dicussed in the next section.


The defendants raised the question of exclusion of testimony under the twin grounds of reliability and relevance under Rule 702 of the Federal Rules of Evidence.

The first challenge that the defendants put forward to the expert testimony was three fold on the ground of lack of reliability.  (a) The defendants claimed that the expert had used NOCSAE headform to conduct helmet tests which was a standard not acceptable to the industry (b) The expert’s test had an unverifiable margin of error because he had not conducted multiple trials of the test and (c) The expert’s equipment must have been incorrectly calibrated because it showed two different peak values for the same average speed.  The Court rejected these claims because although magnesium head forms were used in government testing (DOT compliance testing) , there was no evidence to show that NOCSAE headforms could not perform similarly in a trial. Secondly, the Court held that inability to calculate a margin of error would not make the expert evidence inadmissible. Under Rule 702, the expert was not mandated to conduct multiple tests if he could demonstrate that the variance with each test was very low and would serve no practical purpose Thirdly, the Court opined that average values could have differing peaks in their underlying data and as such no calibration error in Mr. Thom’s equipment could be presumed.

The second contention of the plaintiff was that the expert testimony was not relevant for the jury in this present case. This was because Mr. Thom had used helmets with thinner lining(as compared to what the plaintiff was wearing at the time of the accident) and had increased the drop height to simulate a high side collision. The defendant had not been ejected and hence an increase in drop height was unwarranted. It was also debated as to whether a helmet with a thicker lining would have absorbed the impact of the collision better. The Court however held that these inconsistencies were not enough reason to exclude the testimony under Rule 702. These questions affected the weight of the testimony rather than the admissibility of the expert testimony.

Based on the above reasons, the Court denied the motion of the plaintiff to exclude the expert testimony of Mr. Thom completely.