Private Law Theory

ABSTRACT
While medical experts often opine about causation in medical malpractice lawsuits, mapping the medical literature onto the probabilistic ‘more likely than not’ legal causation standard sometimes goes beyond medical expertise. In many medical malpractice applications, experts cannot utilize the logic of differential etiology and general and specific causation that are common in toxic tort cases, leaving experts without a principled framework for translating from the medical literature onto the legal causation standard. As a result, experts have used different – and sometimes incorrect – approaches to this translation. This is particularly true in stroke litigation, where parties, experts, and sometimes courts have struggled with whether the existing medical research is sufficient to prove legal causation. Using a counterfactual framework, this Essay illustrates the relationship between common epidemiologic effect measures in the medical literature and the probability of legal causation. This Essay also highlights common missteps made by experts, using stroke litigation as an exemplar, and provides guidance for using medical literature to inform causation opinions in medical malpractice litigation.

Hund, Lauren, Moving from Medical Risk to Medicolegal Causation: An Exemplar from Stroke tPA Litigation (February 2, 2026).