During the 1970's, as recording techniques were polished and sharpened, some practices were used by detective departments to ensure their detected crimes remained at 50 percent of those recorded. At this time the British Home Office Instructions for the Preparation of Statistics Relating to Crime (1971) allowed "crimes" to be detected not only when someone appeared at court and was convicted, but also under various other circumstances. Also included in detected crimes are those where a person is charged and acquitted; crimes "taken into consideration" after conviction; when there is some practical hindrance to prosecution, for example, if the suspect dies or if the victim and key witnesses are unwilling to provide evidence; when a person admits a crime and is cautioned or is under the age of criminal responsibility; and when a person who is already serving a custodial sentence admits a crime, but it is decided that no useful purpose would be served by proceeding with the charge. Under these conditions, it may be possible for a dead man to provide a crime clearance, and a minor theft from a shop "taken into consideration" can be set against an unsolved robbery to provide a 50-percent detection rate. Also, an inmate can "clear his slate" and perhaps give the divisional "clear-up" team 50 detections for little or no effort. These and other questionable practices for manipulating police statistics are examined. 8 notes