 The second of Posner’s claims, that the common law ought to be efficient, also presents multiple ambiguities. Do we interpret the claim as a theory of adjudication (i.e., as a theory of how common law judges ought to decide cases)? Or should we understand the claim as asserting that efficiency is the appropriate criterion against which to assess judicial performance? Or should we understand the claim as asserting that lawmakers, whether judges, legislators, or administrators, should choose efficient rules?