Abstract: Defendants litigate common questions in mass tort claims from the posture of a de facto class action, allowing them to exploit economies of scale. In contrast, plaintiffs' claims are rarely 100% aggregated, preventing plaintiffs from making the optimal investment in common questions to maximize the aggregate and individual value of their claims. This Essay explains the advantages of scale economies and discusses the social costs of the systemic bias favoring defendants over plaintiffs. The author argues that this systemic bias can be corrected through mass tort class actions.