The study of crime in a single country is fraught with difficulties, which are compounded when comparing crime in several countries. As we all know, crime statistics as provided by the police and the courts are a rather imperfect measure of actual crime levels. They tell us as much about reporting and recording procedures as they do about crime itself. Countries with different legal systems both define and record criminal acts in different ways. These differences are compounded further by an attempt to compare crime trends over time, as recording practices may change.