The report analyzes the number of rapes and sexual assaults which are reported to patrol, but are never officially recorded or further investigated, and the differences in cases which are handled informally from those for which a formal report is prepared. Also studied are the factors which affect decisions concerning charge classifications, factors which influence the patrol officers' decision to collect physical evidence, request a crime-scene search, or take the victim to a hospital for a physical examination. The factors which affect an officers willingness to submit a detailed offense report for use by investigators are studied. The data was gathered by monitoring each stage of the processing of all rape/sexual assault complaints filed within a 6-month period in a large metropolitan county. 20 references, 8 notes, 5 charts, 30 tables, 5 figures. (Author abstract modified)