Use of Epidemiological and Geostatistical Methods to Understand the Epidemic of Homicides in Baltimore, 2005 to 2017

Violence is widely recognized as a public health problem. Baltimore, Maryland, a city 45 miles north of Washington, DC, has experienced homicide rates several times higher than those experienced by the United States as a country since at least 1975. Since 2015, Baltimore City has experienced an epidemic of homicides, with an average homicide rate of over 50 homicides per 100,000 residents. We analyzed the individual social characteristics of the victims of homicide in Baltimore City between 2005 and 2017. We used descriptive epidemiology to understand the distribution of social risk factors for victimization in individuals. We also used information on the location of homicides in this time period — along with socioeconomic information on Community Statistical Areas (CSA) — to understand the association between neighborhood environmental characteristics and the homicide rates in those CSAs. We finally took inventory of violence prevention programs existing in Baltimore City as of 2017, and we compared the goals of those programs with the findings from the analysis of victims and the victim location. Through the use of epidemiological and geostatistical methods, we found that not all segments of the population of Baltimore City experienced the same levels of homicide victimization. African American men between the ages of 15 and 34 made up over 61% of the homicide victims between 2005 and 2017 in Baltimore City. Most of the homicides showed spatial clustering around CSAs with elevated levels of poverty and disorder (e.g. broken street lights). Hot spot analysis using person, place, and time showed that hot spots tended to appear or disappear depending on the year of the homicides. The government and civil society in Baltimore City are working in different ways to address violence. Existing programs would do well to expand into the emerging hot spots of homicides, while other programs would probably have a greater impact on violence if they combined efforts and focused on a specific segment of the population. Finally, there is a great opportunity for healthcare providers to treat violence with the same approaches as other public health problems