Comparative Causation

This article examines the criterion of comparative causationaccording to which an accident loss is apportioned between afaultless tortfeasor and an innocent victim on the basis oftheir relative causal contributions to the loss. To explainthe rule's structural features, we consider a scenario whereliability is allocated on the basis of causation, regardlessof fault. While this model brings to light several interestingfeatures, it also unveils the limits of such a criterion withrespect to induced activity and care levels. Next we extendthe model to consider the comparative causation rule in conjunctionwith negligence rules. Applying the comparative causation ruleunder a negligence regime induces a combination of incentivesthat is not provided by any known liability rule.