Duty of care cannot be used anymore as the touchstone to differentiate negligence from strict liability, because the scope of liability (traditionally called proximate causation) requirement replicates many of the former features. Indeed, under a negligence rule the marginal Hand formula is applied twice: first to assess whether the defendant did breach his or her duty of care, and, second, to delimit whether defendant's behavior was a proximate cause of the harm suffered by the victim. But under a strict liability rule, the Hand formula question is applied only once when the proximate causation question is raised. Traditional law and economics analysis has almost always taken normative questions raised by the causation requirement as given, which is a major flaw of mainstream models, because the centrality of the scope of liability or proximate causation requirement in real legal practice is disregarded if not simply expelled from the analysis. Then, definining the subjective scope of liability, that is to say, the boundaries of the pool of potential defendants, is the basic policy decision in each an every liability rule. In the model presented in this paper, the government first chooses efficient scope of liability, and, second, given the scope of liability, the government decides liability rule and damages that guarantee efficient precaution. In the final part of the article, most known scope of liability doctrines developed by both common law and civil law systems are described in order to show how large the common ground between negligene and strict liability can be.
Available at: http://works.bepress.com/nunogaroupa/42/