General Causation

General causation is the threshold scientific question in a toxic tort or pharmaceutical mass tort of whether the product or substance at issue is capable of causing the type of injury the plaintiffs allege, established through epidemiological studies, toxicological data, biological mechanism evidence, and expert analysis applying an accepted methodology such as the Bradford Hill criteria. General causation is litigated docket-wide rather than claim by claim, because the scientific question — can this drug cause this cancer, can this chemical cause this disease — does not vary from plaintiff to plaintiff, which is why MDL transferee courts typically resolve it through a single, consolidated Daubert proceeding applicable to the entire docket. A ruling excluding the plaintiffs' general causation experts is frequently case-dispositive for the entire MDL, because without admissible evidence that the product can cause the alleged injury at all, no individual plaintiff can proceed to prove that it did cause their specific injury. Conversely, admission of plaintiffs' general causation experts under Daubert v. Merrell Dow Pharmaceuticals and Federal Rule of Evidence 702 is typically the single most significant valuation event in a mass tort docket's life, since it validates the scientific premise underlying every claim on file.

General causation is the binary gate through which an entire docket's value passes, making it the highest-priority diligence item before committing docket-level capital — a funder is effectively underwriting the odds that a single Daubert ruling goes the plaintiffs' way. Sophisticated funders commission independent scientific review of the general causation literature before deployment rather than relying solely on plaintiffs' retained experts.

Capital deployment is typically structured to concentrate exposure after a favorable general causation ruling rather than before it, treating the pre-ruling period as uninsurable event risk regardless of the underlying merits of individual claims.