A deterrence study of the death penalty in Illinois, 1933–1980

The study analyzes the effect of executions and the death penalty on homicides in Illinois. A forty-eight year time series (1933–1980 inclusive) is used as the basis for this analysis. The first series of results are presented in a graph of executions and homicides by year. A second portion of the analysis compares the mean homicide rates for three time periods—years with executions, years when the death penalty was allowed but no executions were performed, and years in which the death penalty was abolished by the U.S. Supreme Court. No notable differences in homicide rates were observed for these three eras. Finally, a regression analysis was performed which included a lag structure and several relevant controls. The deterrence measure (executions) made no contribution to the variation in homicide rates. Thus, the authors conclude that there is no deterrent effect for the death penalty on homicides in Illinois.