The discussion notes that countries differ in their social, economic, and political characteristics, but the components of the criminal justice system are central to the constitution of every nation-state. The index quantitatively measures the performance of national criminal justice systems in three areas: equity, effectiveness, and efficiency. Data from the index are derived from the Fourth and Fifth United Nations Surveys of Crime Trends and Operations of Criminal Justice Systems and from the third edition of Charles Humana's World Human Rights Guide, published in 1992. The equity data are current as of 1991, whereas the efficiency and effectiveness data are from 1990. The measures are combined into a single performance index for 47 countries. The analysis notes that although the creation of a valid and reliable index is threatened by the potential for ethnocentricism and other forms of bias, it is possible to reduce this risk to a minimum. The analysis concludes that an unbiased assessment of criminal justice performance could be a useful tool for holding countries accountable for the decisions they make concerning their criminal justice systems and therefore may have useful implications for international domestic and foreign policy. Figure, tables, notes, and 75 references (Author abstract modified)