To make the transition from immature to mature mass tort litigation, plaintiffs' lawyers must establish a credible threat to prevail at trial. One way to make this transition is to establish the merits of the litigation. But that is not the only way. Additional claims may come into the tort system for other reasons: due to inaccurate information about the merits of the litigation sent by early lawsuits at the immature stage or through the aggregation of litigation at that stage, through the certification of a class action. The workings of this process and the efforts of the civil litigation system to regulate it form the subject of this chapter.
The story of mass tort litigation over the safety of silicone gel breast implants illustrates the problem of inaccurate information about claim merit. A useful starting point for discussion of aggregation focuses on litigation over HIV-contaminated blood products. In casting the discussion along these lines, this chapter ties together two topics that have garnered much attention in scholarship on civil litigation in recent decades:first, the rise of a “gatekeeper” role for trial judges with respect to the admissibility of expert scientific testimony, as described in the Supreme Court's 1993 evidentiary decision in Daubert v. Merrell Dow Pharmaceuticals, Inc.;1 and, second, concern over the capacity of litigation on an aggregate basis—most prominently, class actions—to exert undue or illegitimate pressure upon defendants to settle. Each of these topics has spawned a rich literature of its own, and each has repercussions beyond the world of mass tort litigation.2 At bottom, however, both topics arise from the mass tort setting.
A lawsuit over the morning sickness drug Bendectin provided the occasion for the Court's decision in Daubert, though contemporaneous litigation over silicone gel breast implants lays out even more clearly the implica-