would be that laws would be well, but not perfectly, adapted. However, while these notions are interesting, as roe himself admits they do not as of yet provide refutable hypotheses. It would also be interesting to see if these propositions can be generalized to provide some implications In a recent important paper, Zywicki (2003) has added what he calls a"supply side"to the efficiency of law models. He points out that the evolutionary models discussed above are demand side " models, with litigants demanding efficient rules Following Berman(1983), Zywicki shows that during the formative period of the common law there was competition between several court systems. There was first competition between civil and ecclesiastical courts. Within the civil system, there were royal law, feudal law, manorial law, urban law and mercantile law courts, all competing for the fees and business of litigants. There were courts of the King's bench the Exchequer, and the Court of Common Pleas, and four more obscure royal courts as well All of these courts competed for business and fees; for example, church courts jurisdiction over testamentary succession could be used to increase the domain of these courts. This created an incentive for each court to provide unbiased, accurate and quick resolution of disputes. This is the supply side: judges and courts competed to supply efficient rules to get the business of disputants. Courts could also borrow remedies and ules from each other, which facilitated the evolution and spread of efficient rules and In this competition, the Law Merchant (Lex mercatoria) played a major role in commercial law, including contract law(Benson, 1989). Ultimately the common lawwould be that laws would be well, but not perfectly, adapted. However, while these notions are interesting, as Roe himself admits, they do not as of yet provide refutable hypotheses. It would also be interesting to see if these propositions can be generalized to provide some implications. In a recent important paper, Zywicki (2003) has added what he calls a “supply side” to the efficiency of law models. He points out that the evolutionary models discussed above are “demand side” models, with litigants demanding efficient rules. Following Berman (1983), Zywicki shows that during the formative period of the common law there was competition between several court systems. There was first competition between civil and ecclesiastical courts. Within the civil system, there were royal law, feudal law, manorial law, urban law and mercantile law courts, all competing for the fees and business of litigants. There were courts of the King’s Bench, the Exchequer, and the Court of Common Pleas, and four more obscure royal courts as well. All of these courts competed for business and fees; for example, church courts’ jurisdiction over testamentary succession could be used to increase the domain of these courts. This created an incentive for each court to provide unbiased, accurate and quick resolution of disputes. This is the supply side: judges and courts competed to supply efficient rules to get the business of disputants. Courts could also borrow remedies and rules from each other, which facilitated the evolution and spread of efficient rules and remedies. In this competition, the Law Merchant (Lex mercatoria) played a major role in commercial law, including contract law (Benson, 1989). Ultimately the common law 7