The skewing effect of outcome evidence

Behaviours are primarily regulated to reduce the risks of a negative outcome to others. This article discusses the use of outcomes as evidence of violations of a legal standard (outcome evidence). The current debate over outcome evidence centres around limited rationality. Opponents argue that factfinders’ estimations are distorted by hindsight bias, while supporters argue that factfinders properly update the probability of fault, given information about the outcome. The article adopts the rationality assumptions and argues that factfinders should nevertheless disregard outcome evidence in most cases unless the outcome can provide evidence that works for or against the defendant or when the law creates inefficient incentives to comply with the legal standard, then using adverse outcomes as evidence may help solve the problem of undercompliance. The article further shows that when evidence cannot be excluded, changes to the law governing primary behaviour are warranted to account for the distortionary effect of outcome evidence.