The analysis is based on data from 41 police forces in England and Wales, except the Metropolitan and City of London police. The research was designed to measure the impact of police strength and other key factors on force rates. Police resources did affect force rates but not significantly. The results imply that the remedy for declining clearance rates is not to be sought solely in increased police manpower. The clearance of most routine crime derives from the help supplied to the police by the public, rather than from police efforts. Some improvements in the clearance rate might accrue if police forces were to consider alternative methods of investigating crime. Tables, footnotes, and 35 references are included. Appendixes contain clearance rates over time and by offense and methods of crime clearance. (Author summary modified)