Deterrence and brutalization: The dual effects of executions

On April 21, 1992, California received wide national attention when Robert Alton Harris was executed in the gas chamber at San Quentin. Harris's execution marked a reintroduction of the death penalty in California after a 25-year moratorium. We use weekly time-series data on the level and type of criminal homicide incidents in the state from 1989 through 1995 to exploit the quasi-experimental qualities of this naturally occurring “experiment,” and assess the impact of Harris's execution on the incidence of homicide. As in several recent studies, we disaggregate criminal homicides into forms of murder highly likely to be affected by capital punishment: felony-murders of nonstrangers, for which we predict a deterrent effect, and argument-murders of strangers, for which we predict a brutalization effect. On the basis of an autoregressive integrated moving-average approach to time-series analysis, we find (as predicted) a significant decline in the level of nonstranger felony-murders and a significant increase in the level of argument-based murders of strangers in the period following the execution. Moreover, the increase in argument-based stranger murders associated with the Harris execution endured across a subsequent execution period, while the decline in nonstranger felony-murders shifted to the subsequent execution.