ABSTRACT
Micro effi ciency is based on an examination of particular legal doctrines and attempts to determine if they are effi cient. This was the method used by Posner.3 The diffi culty with this method of analysis is that often the conclusion regarding the effi ciency of a particular rule depends on unmeasured transactions costs of various sorts; if the analysts’ intuition about relative magnitudes of costs is incorrect, then doctrines claimed to be effi cient may not be so. Nonetheless, Posner’s analysis has been the intellectual spark behind the growth of law and economics, and questions of effi - ciency of the sort he was the fi rst to raise have dominated the literature. Much of this literature may be considered as detailed attempts to answer the positive effi ciency
question fi rst posed by Posner, and much of the rest aims at deriving normative conclusions as to what is effi cient.
