Common law is generally uncodified. This means that there is no comprehensive compilation of legal rules and statutes. While common law does rely on some scattered statutes, which are legislative decisions, it is largely based on precedent, meaning the judicial decisions that have already been made in similar cases. These precedents are maintained over time through the records of the courts as well as historically documented in collections of case law known as yearbooks and reports. The precedents to be applied in the decision of each new case are determined by the presiding judge. As a result, judges have an enormous role in shaping American and British law. Common law functions as an adversarial system, a contest between two opposing parties before a judge who moderates. A jury of ordinary people without legal training decides on the facts of the case. The judge then determines the appropriate sentence based on the jury’s verdict.
Civil Law, in contrast, is codified. Countries with civil law systems have comprehensive, continuously updated legal codes that specify all matters capable of being brought before a court, the applicable procedure, and the appropriate punishment for each offense. Such codes distinguish between different categories of law: substantive law establishes which acts are subject to criminal or civil prosecution, procedural law establishes how to determine whether a particular action constitutes a criminal act, and penal law establishes the appropriate penalty. In a civil law system, the judge’s role is to establish the facts of the case and to apply the provisions of the applicable code. Though the judge often brings the formal charges, investigates the matter, and decides on the case, he or she works within a framework established by a comprehensive, codified set of laws. The judge’s decision is consequently less crucial in shaping civil law than the decisions of legislators and legal scholars who draft and interpret the codes.