An experimental comparison of adversarial versus inquisitorial procedural regimes

Abstract

This article reports the results of a multiyear series of economic experiments comparing the two dominant types of legal procedures used in adjudication: (1) the “adversarial” model of party-controlled procedure versus (2) the “inquisitorial” model of judge-controlled procedure. The principal finding is that the relative fact-finding efficiency of the two systems, in terms of both the “revelation” of hidden facts and the “accuracy” of decision, depends significantly upon the information structure. Under a “private” information structure, inquisitorial procedure is relatively more efficient, whereas under a “correlated” information structure, adversarial procedure is relatively more efficient.