According to the text, “Crime statistics provide an overview of criminal activity. If used properly, a statistical picture of crime can serve as a powerful tool for creating social policy. Decision makers at all levels, including legislators, other elected officials, and administrators throughout the criminal justice system, rely on crime data to analyze and evaluate existing programs, to fashion and design new crime-control initiatives, to develop funding requests, and to plan new laws and crime control legislation. Many “get tough” policies, such as the three-strikes movement that swept the country during the 1990s, have been based in large part on the measured ineffectiveness of existing programs to reduce the incidence of repeat offending.” (chapter 2 Criminal Justice Today: An Introductory Text for the 21st Century, Eleventh Edition, by Frank Schmalleger. Published by Prentice Hall.)
The clearance rate is calculated by dividing the number of crimes that are cleared by the total number of crimes recorded. Clearance rates can be very problematic for measuring the performance of the police services and for comparing different police services and this is possible because different police forces may employ a different way of measuring clearance rates. I think the number of clearance rates will vary depending on the crime rates in the precinct, reported or unreported. The crime rates relate to arrest rates as indicted by the Uniform Crime Report (UCR) and possibly the