Affirming summary judgment in an alleged defective lifeline cable case in which the plaintiff decided to proceed with lay testimony after his expert was excluded under Daubert, the U.S. Fifth Circuit held as follows:

“To be sure, expert testimony is not required in every LPLA case. Plaintiffs may sometimes rely on lay testimony alone. But Appellants read too much into this Court’s statement that ‘there may be cases in which the judge or the jury, by relying on background knowledge and “common sense,” can “fill in the gaps” in the plaintiff’s case … without the aid of expert testimony.’  As both this Court and Louisiana courts have recognized, for expert testimony not to be required in a products liability case, ‘the product itself, or at least the … feature in question, must be relatively uncomplicated, and the implications … such that a layman could readily grasp them.’  Consequently, courts consistently require expert testimony in products liability cases, even when the products in question are in common use.

“To find injury causation here, a jury would at least have to conclude that a different lifeline cable or a different warning would have, under the circumstances of this accident, prevented Stewart’s death.  Thus, a jury would be confronted with questions that require a degree of familiarity with such subjects as physics, engineering, and oil rig practices and procedures.  This case therefore raises questions that are of ‘sufficient complexity to be beyond the expertise of the average judge and juror’ and that ‘common sense’ does not make obvious. Accordingly, Appellants were required to provide the jury with expert testimony related to causation in order to survive summary judgment in this case.”


Stewart v. Capital Safety, No.16-30993, 2017 WL 2347612 (5th Cir. May 30, 2017).