This paper presents the study of the ideological foundations that inspired the process of codification of the law which took place in the nineteenth century and had as a benchmark regulatory maximum the law, this paradigm was surpassed in the twentieth century by the great process of issuing special laws relegated to a second tier to the coded bodies. Besides the role in postwar constitutional states took the judges, and therefore judicial precedent as a formal source of law, all of which represented a strategic shift of the judicial function in the operation of contemporary states arises. The new role that justice and judicial precedent assume is influenced by the neo-institutional economic theory, which focuses its analysis on the study of institutions and the relationship that they have with the market economy. The case of judicial precedent is paradigmatic in the relation of law and neo-institutional economics, because this source of law established jurisprudential and backed by legislation can provide market predictability, safety and regulatory unit in the early nineteenth century were guaranteed by the code.