1 Quality of Chicago Supplementary Homicide Reports Data Compared to the Chicago Homicide Dataset

The Supplementary Homicide Reports (SHR) of the Uniform Crime Reports has been for many years a foundation of homicide research In the United States (Maltz, 1999). The SHR is easily accessible, available in the National Archive of Criminal Justice Data (Fox, 1996), and contains more detail about each incident than available in the Uniform Crime Reports for other violent crimes. Policy decision-makers depend upon it to answer such basic questions as the trends in homicide rates of young offenders (Fox, 1997), the effectiveness of gun-carry laws (Lott & Mustard, 1997), the risk of death due to child abuse (Maltz, 1998), the number of domestic violence homicides (Langford, et al., 1998), or the proportion of homicides committed by a stranger (Riedel, 1998; Williams & Flewelling, 1987). Since the SHR has been and continues to be the source of much of our know-ledge about lethal violence in the United States, it is important to know just how good that source is. Is the SHR complete enough and accurate enough to be a basis of policy decisions? To evaluate the completeness and accuracy of SHR data in one city, the Bureau of Justice Statistics (BJS) asked the Illinois Criminal Justice Informa-tion Authority to conduct a case-by-case comparison of the 1,784 homicides recorded in the Chicago Homicide Dataset (CHD) in 1993 or 1994 to homicides recorded in the SHR for those years. BJS wanted to know whether SHR data on offender characteris-tics was systematically different from data in police files, and if so, to describe those differences. The results provide information about the quality of SHR data in Chicago, and by extension, about SHR quality in other cities with similar situations