When it comes to mass tort cases, full diversity of citizenship is essential. This means that no plaintiff and defendant should be domiciled in the same state. To determine if a diversity jurisdiction exists, courts must consider a variety of factors. These include the factual reality of the cases, the incentives created by the special risk profile of mass litigation, the potential for future plaintiffs, and the conflicts of interest between parties and lawyers. For defendants, grouping cases together and reaching a comprehensive resolution of mass litigation offers a way to limit their exposure.
However, when mass grievances involve several defendants with varying degrees of exposure, they may not be able to agree on a favorable overall solution. It is important to recognize how litigation is driven by the asymmetric risks faced by plaintiffs' lawyers and defendants. The media and the evolution of plaintiff law firms have also played a role in facilitating the filing of massive tort lawsuits. If a massive tort litigation is resolved by aggregating and creating a compensation fund, that fund can be paid and the rest of the litigation can be resolved through a claims service. For example, medical devices, which until 1976 were not subject to FDA review, are well represented in mass tort litigation. Because of these commonalities between issues and actors, the added value of all the lawsuits in the same massive grievance increases and decreases depending on the results of individual cases or with other critical events. Because global resolutions are so difficult to achieve, courts and parties often try to make partial resolutions in mass tort litigation.
This could involve guaranteeing the payment of cases filed against some defendants or filed in a particular jurisdiction. Product liability law has also given victims of mass-injured accidents the opportunity to sue product manufacturers with common plaintiffs. Most reform proposals focus on procedure rather than substantive doctrine, and are aimed at increasing the capacity of judges to achieve global resolutions in mass tort litigation. Asymmetric and enormous scale risks can drive massive tort litigation, expanding their reach to the limits of the defendant's available assets or the limits of exposed individuals willing to sue. The advantages and disadvantages of these services illustrate how the special nature of collective tort litigation interacts with reform proposals. When determining if there is enough diversity among plaintiffs to proceed with a mass tort case, all these factors must be taken into consideration.