Can competing expert opinions defeat summary judgment in product liability cases? Best v. Daimler Chrysler Corporation Explained

In Best v. Daimler Chrysler Corporation, the Utah Court of Appeals addressed whether competing expert opinions on the cause of an airbag malfunction precluded summary judgment in a product liability case. The decision provides important guidance on when expert disagreements create genuine issues of material fact.

Background and Facts
Plaintiff purchased a used 1993 Chrysler that was involved in two accidents requiring repairs using aftermarket parts. In 1999, the driver’s airbag deployed unexpectedly while driving in a parking lot, allegedly injuring plaintiff. Defendants’ expert concluded that improper steering repairs caused clockspring damage, leading to a short circuit and premature deployment. Plaintiff’s expert disagreed, attributing the malfunction to defective airbag components based on diagnostic readouts and photographs, without conducting a physical inspection.

Key Legal Issues
The court addressed two primary issues: (1) whether competing expert methodologies and conclusions created genuine issues of material fact precluding summary judgment, and (2) whether the trial court properly allowed plaintiff to substitute expert witnesses after the original expert became unavailable.

Court’s Analysis and Holding
The court of appeals reversed the summary judgment, emphasizing that it is not the purpose of summary judgment to judge witness credibility or weigh evidence. The court found that plaintiff’s expert sufficiently disputed defendants’ conclusions about both the proper diagnostic method and the source of the defect. Regarding the diagnostic methodology, the court noted that determining whether physical inspection was necessary would require weighing expert opinions, which is reserved for the fact finder. The expert’s explanation for apparent contradictions between his deposition and affidavit testimony was adequate to avoid disregarding the affidavit.

Practice Implications
This decision reinforces that competing expert opinions typically preclude summary judgment, even when experts disagree on methodology. Practitioners should ensure expert affidavits provide sufficient factual basis rather than mere conclusions. When expert testimony appears contradictory, adequate explanations for discrepancies between depositions and affidavits can preserve the testimony’s viability. The court’s broad discretion regarding expert witness substitutions also demonstrates the importance of properly designating experts initially while recognizing that courts may allow substitutions to advance case resolution.