The Deterrent Effect of Expansions in Death Penalty Eligibility Criteria

Homicides must possess certain characteristics before they become eligible for capital punishment. Over the last several decades, virtually every state has added to its list of possible eligibility criteria. We draw on this variation to identify deterrent effects of the eligibility expansions. Eligibility expansions may deter future homicides through two channels: (1) by paving the way for more death sentences and executions and (2) by providing prosecutors with greater leverage to secure enhanced sentences (capital or non-capital). The latter channel is likely to be triggered on a fairly common basis. We estimate that the adoption of a law making child murders specifically eligible for capital punishment is associated with an approximately 19% reduction in the rate of homicides of youth victims. We estimate deterrence findings of similar magnitude when we turn to the estimation of an empirical specification that draws on variations in the full set of eligibility criteria and that parameterizes general eligibility statutes using a simulated measure of the propensity of each state to extend capital eligibility to a given murder. However, the findings of this general deterrence investigation are relatively noisy and are not robust to the exclusion of the child-murder factor from the simulation analysis.