The Deterrent Effect of Capital Punishment: Evidence from a “Judicial Experiment”

Abstract

We use panel data for 50 states during the 1960-2000 period to examine the deterrent effect of capital punishment, using the moratorium as a ''judicial experiment.'' We compare murder rates immediately before and after changes in states' death penalty laws, drawing on cross-state variations in the timing and duration of the moratorium. The regression analysis supplementing the beforeand-after comparisons disentangles the effect of lifting the moratorium on murder from the effect of actual executions on murder. Results suggest that capital punishment has a deterrent effect, and that executions have a distinct effect which compounds the deterrent effect of merely (re)instating the death penalty. The finding is robust across 96 regression models. (JEL C1, K1)

Estimating the Impact of the Death Penalty on Murder

“…proposition by running a regression with a "law dummy" indicating the presence of a capital punishment law. First, using data from 1960-2000, Dezhbakhsh & Shepherd (2006) reported that the coefficient on the law dummy was negative (that is, finding deterrence) and statistically significant. DW showed, however, that this result became insignificant when the standard errors were adjusted by clustering and when year fixed effects were added to the regression (as is standard) (see Table 2 of Donohue & Wolfers 2005).…”

“…executions (following Dezhbakhsh and Shepherd, 2006), 2) the ratio of executions to either population or murders (following DW), 3) the ratio of executions to prisoners (following KLS), or 4) the ratio of executions to death sentences (following DRS, MG, and Zimmerman).…”

“…Unlike Dezhbakhsh & Shepherd (2006) and KLS used only a measure of executions (rather than a law dummy) to capture the influence of the death penalty. By so doing, they are testing the behavioral model that the impact of the death penalty is zero until executions occur and that executions only impact the murder rate for the year following the execution.…”

Criminal Deterrence: A Review of the Literature

“…In particular, these studies have exploited the fact that in addition to cross-state differences in sentencing policy, there is also variation over time for individual states in the official sentencing regime, the propensity to seek the death penalty in practice, and the application of the ultimate punishment (Chalfin, Haviland, and Raphael 2013). This literature has generated mixed findings with several prominent papers (e.g., Dezhbakhsh, Rubin, and Shepherd 2003;Mocan and Gittings 2003;Zimmerman 2004Zimmerman , 2006and Dezhbakhsh and Shepherd 2006) finding large and significant deterrence effects, and several equally prominent papers (Katz, Levitt, and Shustorovich 2003;Berk 2005;Donohue andWolfers 2005, 2009; and Kovandzic, Vieraitis, and Paquette-Boots 2009) finding little evidence in favor of deterrence.…”

Econometric Estimates of Deterrence of the Death Penalty: Facts or Ideology?

“…H. DEZHBAKHSH and J.M. SHEPHERD (2006) find that the abolition of the death penalty was associated with an increase while its reintroduction led to a (smaller) decrease of homicides, but J.J. DONOHUE and J. WOLFERS (2005) using a difference-in-difference approach do not find any evidence in this respect. Moreover, DEZHBAKHSH and J.M.…”