In this Article, Professor Fisch assesses currrent retroactivity doctrine and proposes a new framework for retroactivity analysis. Current law has failed to reflect the complexity of defining retroactivity and to harmonize the conflicting concerns of efficiency and fairness that animate retroactivity doctrine. By drawing a sharp distinction between adjudication and legislation, the law has also overlooked the similarity of the issues that retroactivity raises in both contexts. Professor Fisch's analysis, influenced by the legal process school, uses an equilibrium approach to connect retroactivity analysis to theories of legal change. Instead of focusing on the nature of the new legal rule, this approach emphasizes the context in which change occurs. If an area of the law is settled, a stable equilibrium, reliance interests are at their peak. Retroactivity thus presents serious fairness and efficiency concerns and should be disfavored. If the regulatory context is in flux, an unstable equilibrium exists, and retroactivity may be more appropriate . Professor Fisch's use of equilibrium theory improves doctrinal analysis of the temporal line-drawing associated with legal change and clarifies the relationship of retroactivity rules to lawmaking powe1·.
Fisch, Jill E., "Retroactivity and Legal Change: An Equilibrium Approach" (1997). Faculty Scholarship at Penn Law. 892.