the error rate” of Lafferty’s technique, and no basis for determining whether Lafferty’s “methods are consistent with the generally accepted method for gathering and evaluating evidence in the field of biomechanics and mechanical engineering as applied to occupant dynamics and restraint system efficacy in motor vehicle accidents.” Id. at 15. Because the court was “unable to determine what methodology or reasoning, if any, serves as the basis for Dr. Lafferty’s opinions,” and because “Lafferty offers nothing more than subjective belief and unsupported speculation,” his testimony was “not based on a reliable methodology” and thus was inadmissible under Rule 702. Id. at 15, 16, 18.
Clark offers virtually no answer to the district court’s first rationale — that Lafferty’s opinion about whether Clark’s belt came unlatched was “not helpful to the trier of fact” (NR 87:16; see Fed. R. Evid. 702), because Lafferty had elsewhere admitted under oath that he “didn’t address that question,” “ha[d]n’t considered it,” and “ha[d] no opinion on that.” NR 47:Tab 11 at 80. Clark implies that the district court, in stating that Lafferty “was assuming” that Clark’s “unlatched during the accident sequence,” misunderstood Lafferty’s testimony. NR 87:16; AOB 22 (emphasis omitted). Thus, Clark repeatedly underscores the phrase “during the accident sequence” in an effort to suggest that Lafferty’s assumption was of limited scope (limited, that is, to whether the belt became unlatched during, rather than before or after, the accident). AOB 22, 28. This argument fails for several reasons. First, it is nonsensical. According to the undisputed testimony of Clark himself, he fastened his lap belt prior to the accident. And whether the belt unbuckled after the accident is plainly irrelevant to liability here. Thus, the only pertinent question is whether the lap belt failed during the accident. Lafferty’s emphatic testimony, however, was that he “ha[d] no opinion” on that question.
Second, Clark did not argue in the district court that Lafferty’s express disclaimer of any opinion concerning whether the belt became unbuckled was limited to unbuckling “during the accident sequence” (or that such a limitation was pertinent to the admissibility question). In requesting summary judgment, defendants contended that “Dr. James