The findings show that significant increases occurred in the likelihood that police would be notified of alleged sexual-assault crime and other forms of assault. These increases were observed for both violence against women and violence against men, for stranger and nonstranger violence, and for crimes committed against members of various racial/ethnic groups. Reports to police of property crimes (i.e., motor vehicle theft, burglary, and larceny) also increased across the study period. The observed increase in crime reporting accounted for approximately half of the divergence between data from the NCVS and the Uniform Crime Reporting Program (UCR) in the estimated magnitude of the 1990s crime decline. The finding emphasizes to need to corroborate findings about crime trends from multiple data sources. The study integrated data from the NCS for 1973 to 1993 and for the NCVS from 1992 to 2005. These data were derived from surveys of persons ages 12 years old and older from a representative sample of U.S. households. The surveys focused on respondents' experiences with and reactions to criminal victimizations during the previous 6 months. Among the questions asked in the interviews were whether victimization incidents were reported to the police. The NCS and the NCVS are the only national-level data sources in the United States that contain information about crimes that did not come to the attention of the police. Crime incidents were the units of analysis for the study. 5 tables, 4 figures, and 59 references