“Delaware Supreme Court Shuts Down Flawed Expert Testimony,” Bloomberg Law
publication | August 7, 2025
Bloomberg Law published an article authored by Hollingsworth LLP partner Shannon Proctor, which explores how the Delaware Supreme Court’s consequential ruling for mass tort litigation and expert admissibility standards in In re Zantac (Ranitidine) Litigation can be used as a guide for expert admissibility in state and federal courts. The ruling, which reversed a decision to admit plaintiffs’ expert testimony in a sprawling personal injury case that ranitidine (sold under the brand name Zantac) caused cancer, adds to the body of legal authority correcting prior errors and holding proponents of expert testimony to their proper admissibility burden.
The trial court’s ruling reflects the improperly lax review of expert testimony that led to public calls for the amendment to FRE 702. The trial court claimed Delaware’s rule embodies a “liberal thrust favoring admission,” differentiating it from the federal rule, and that methodological criticisms raised by defendants went to the “weight,” not the admissibility, of the experts’ testimony.
Central to the decision is the court’s interpretation of Delaware Rule of Evidence 702, its alignment with Federal Rule of Evidence 702, and the trial judge’s gatekeeping obligations.
- First, the court made clear that “Delaware follows the federal standard.”
- Second, the trial court’s “liberal thrust” interpretation was rejected.
- Third, the court found the trial court abdicated its gatekeeping role by treating major methodological flaws—including cherry-picking data, reliance on animal and occupational NDMA studies unrelated to ranitidine, and lack of a dose-response analysis—as jury issues.
- And finally, the court took umbrage with the trial court’s framing of the general causation inquiry.
For lawyers litigating mass torts, the message is clear: Scientific rigor, methodological transparency, and strict adherence to Rule 702 are non-negotiable prerequisites for expert testimony to reach a jury.
Reproduced with permission. Published August 7, 2025. Copyright 2025 Bloomberg Industry Group