THE STOCHASTIC-DOMINANCE OF NO-FAULT AUTOMOBILE INSURANCE

This article presents a rigorous analysis of no-fault automobile insur ance in terms of stochastic dominance theory. In the baseline case, wi th identical drivers and actuarially fair insurance, no-fault is stoch astically dominant as long as the no-fault insurance premium exceeds t he tort premium. In this case, no-fault brings a higher proportion of accident costs under insurance, increasing driver welfare. When expens e charges are introduced (actuarially unfair insurance) no-fault may s till be stochastically dominant if the expense charge is less under no -fault, even if no-fault weakens incentives for good driving and leads to higher accident rates. Elective no-fault is unlikely to reduce aut o insurance costs, because drivers with high propensities toward moral hazard are likely to retain their fight to sue by choosing tort.