The dynamic relationship between homicide rates and social, economic, and political factors from 1970 to 2000*.

After reaching their highest levels of the 20th century, homicide rates in the United States declined precipitously in the early 1990s. This study examines a number of factors that might have contributed to both the sharp increase and decline in homicide rates. We use a pooled cross-sectional time series model to assess the relationship between changes in structural conditions and the change in homicide rates over four decennial time points (1970, 1980, 1990, and 2000). We assess the extent to which structural covariates associated with social, economic and political conditions commonly used in homicide research (e.g., urban decay, poverty, and the weakening of family and social bonds) are related to the change in homicide rates. Along with these classic covariates, we incorporate some contemporary explanations (e.g., imprisonment rates and drug trafficking) that have been proposed to address the recent decline in urban homicide rates. Our results indicate that both classic and contemporary explanations are related to homicide trends over the last three decades of the 20th century. Specifically, changes in resource deprivation and in the relative size of the youth population are associated with changes in the homicide rate across these time points. Increased imprisonment is also significantly related to homicide changes. These findings lead us to conclude that efforts to understand the changing nature of homicide will require serious consideration, if not integration, of classic and contemporary explanations.