Gun Homicide Deaths of People on Probation (Preliminary)

In March of 2022, the Adult Probation Department (APD) worked with partners from Cook County Health (CCH) and the Medical Research Analytics and Informatics Alliance (MRAIA) to use a privacy-protecting algorithm (Linkja) to match active probation records with gun homicide death records from the Cook County Medical Examiner’s Office (CCME). The main goal of the partnership was to develop a baseline rate of gun homicide deaths for people on probation to support operational and grant application activities. APD submitted a hashed roster of 53,964 unique individuals who had been active on probation during 2018 through 2021. These hashed records were matched to 306 hashed records of gun homicide deaths in the CCME data.

This preliminary analysis indicates that the rate of gun homicide deaths per 100,000 probation clients is 567. This is almost 22 times higher than the overall gun homicide rate for the City of Chicago in 2020, which was 25 gun-related homicides per 100,000 population, and almost 33 times higher than the gun-related homicide rate for Cook County in 2020, which was 16.87 deaths per 100,000.

Mortality Comparisons - All Victims

Preliminary analyses were conducted using the entire CCME dataset of gun homicide deaths for this period, with a flag for those who were matched to a probation case. Overall, there were 3,728 gun homicides in the CCME data, with an average age of 33.65 at death. Almost 91% were male (n=3,374), 71% were Black (n=2,650), and about 86% were non-Hispanic (n=3,192). Compared to those not in the probation data, the probation clients tended to be younger (29.43, p<.001) and were more likely to be Black (89% vs. 69.5%; p<.001). See Table 1 for a breakdown of demographic characteristics by probation status.

Table 1: Demographic Comparisons by Probation Status

Mortality Comparisons - APD Victims

Data on gun-related homicides were matched with APD demographic and case-related data to examine differences in mortality rates by certain individual characteristics. This preliminary analysis included two variables for comparison – age at probation start and type of offense.

Age at probation start was analyzed as discrete categories: under 18, 18-25 (emerging adults), 26-35, 36-45, 46-55, and over 55. The two largest age categories in the probation population during this time period were the 26-35 age group (n=17,628; 32.7%) and the 18-25 age group (n=16,275; 30.2%). Of the adult clients in this sample, the emerging adult group had the highest homicide rate, which was significantly higher than the overall population (970.8 per 100,000; p<.001). This group accounted for over half of all homicide victimizations, while comprising less than a third of the probation population. See Table 2 for a comparison of homicide rates by age categories.

Table 2: Homicide Rate Comparisons by Age

Conviction offense was grouped into several categories: person, property, drug, sex offense, DUI, weapons, and other. Drug and property offenses were the largest groups in the probation population during this period, comprising 24.8% and 23.5% of the population, respectively. Probation clients convicted of weapons-related offenses had the highest homicide rate, which was significantly higher than the probation population (919.3 per 100,000; p=.001). Clients on probation for drug-related offenses also had a significantly higher homicide mortality rate than the overall population (801.0 per 100,000; p=.002). See Table 3 for a comparison of homicide rates by offense type.

Table 3: Homicide Rate Comparisons by Conviction Offense