Crime rate and clearance rate, commonly used as measures of police performance, are widely criticized for their methodological weaknesses and limited utility. The evaluation of police performance based on these indicators may also be challenged as reflecting only the crime control function of policing. If, as Wilson (1968) suggests, police organizations vary in the degree to which they conform to a legalistic approach to law enforcement, then an indicator of police performance must reflect the organization's adherence to due process in protecting citizen's rights, as well as crime control. The application for a warrant, the final stage in the police organization's processing of a case, deserves attention as the point of output for the police and input for the prosecutor's office. The issuance of a warrant by the prosecutor's office validates the arrest, acknowledging compliance with due process. In addition to measuring police performance in the due process area, analysis of warrant data illuminates system needs from a unique vantage point. As the ratio of warrants sought to warrants issued increases for specific offenses, this change can signal the need for the type of attention that would not be forthcoming following an increase in the crime rate or a decrease in the clearance rate. Further, an analysis of warrant data by subunits would pinpoint those whose level of performance is atypical. System needs and issues of due process may also be examined with reference to accusations of police abuse of power and discrimination. References and tabular data are provided. (Author abstract modified)