The study found that relatively few rapes involved co-occurring crimes. According to the National Crime Victimization Survey (NCVS), 17 percent of rapes occur with an additional crime, and the National Incident-Based Reporting System (NIBRS) indicates that only 67 percent of rapes co-occur with other crimes. This subset of rape cases, however, carries a number of increased risk factors for victims. Such rapes are more likely to involve weapons, strangers, additional injury to the victim, and multiple offenders. Rapes with co-occurring crimes are more likely to be reported to police than rapes without additional crimes. These cases are also more likely to be cleared by police than rapes committed with no other crimes involved. The study used two national data sources that collect the required incident information. One source (NCVS) obtains self-reported information from individuals regarding criminal victimizations they have personally experienced, whether or not they were reported to police. The second data source contains information on crimes known to the police (NIBRS). 5 tables and 61 references