126 F.4th 1213
6th Cir.2025Background
- Timothy Davis was injured when his Sig Sauer P320 X-Carry pistol discharged while he exited his truck; he claims the gun was holstered, and he did not pull the trigger.
- Davis sued Sig Sauer in Kentucky state court under strict liability and negligence theories for an alleged design defect, arguing safer alternative designs existed.
- Sig Sauer moved to exclude Davis’s experts (firearms and human factors) and for summary judgment, arguing lack of admissible expert causation testimony.
- The district court excluded both experts' testimonies, holding neither sufficiently investigated the incident's facts to opine on causation; summary judgment was granted to Sig Sauer.
- The Sixth Circuit affirmed exclusion of expert testimony specifically on causation, but reversed as to their opinions on design defect and alternative designs, vacated summary judgment, and remanded for trial.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Admissibility of expert opinions on causation | Experts can help jury infer causation through design testimony | Experts did not analyze the incident so can't opine on causation | Experts' causation opinions properly excluded; lack sufficient factual basis |
| Admissibility of expert opinions on design defect/alternatives | Experts support claim P320 is defectively designed, offer options | Opinions should be excluded entirely due to causation flaws | Expert opinions admissible to show design defect and alternatives even if not on accident's causation |
| Need for expert testimony on causation in complex product defect | Not needed for causation here; lay jury can understand | Required in technical cases like this | Expert not needed on causation; lay jurors can decide, given evidence, how design may have caused the injury |
| Entitlement to summary judgment | Genuine disputes exist; evidence admissible on defect/design | No admissible expert causation evidence, so claims must fail | Summary judgment vacated; dispute of material fact exists |
Key Cases Cited
- Smith v. Wyeth, Inc., 657 F.3d 420 (Sixth Circuit defines Kentucky product liability action under the Products Liability Act)
- Toyota Motor Corp. v. Gregory, 136 S.W.3d 35 (Ky. 2004) (Kentucky applies risk-utility test to design defect cases and requires proof of a feasible alternative design)
- Nichols v. Union Underwear Co., 602 S.W.2d 429 (Ky. 1980) (Factfinder decides if product design was unreasonably dangerous)
- Holbrook v. Rose, 458 S.W.2d 155 (Ky. 1970) (Legal causation can be established by circumstantial evidence in Kentucky products claims)
- King v. Ford Motor Co., 209 F.3d 886 (Sixth Circuit, describing substantial factor test for causation in products liability under Kentucky law)
- Caniff v. CSX Transp., Inc., 438 S.W.3d 368 (Ky. 2014) (Expert evidence unnecessary on causation when issue within lay understanding)
- Primal Vantage Co. v. O’Bryan, 677 S.W.3d 228 (Ky. 2022) (Design defect claim requires proof of a safer, feasible alternative design)