Comparative Vigilance

A growing body of literature suggests that courts and juriesare inclined toward division of liability between two strictlynon-negligent or "vigilant" parties. In this paper, we explorethe economic efficiency of liability rules based on comparativevigilance. We devise rules that are efficient and that rewardvigilance. Commonly used liability rules have discontinuousliability shares. We develop a liability rule, which we callthe "super-symmetric rule," that is both efficient and continuous,that is based on comparative negligence when both parties arenegligent and on comparative vigilance when both parties arevigilant, and that is always responsive to increased care.