RESEARCH: Halting the Use of the Death Penalty Did Not Result in an Increase in Homicide Rates

Stephen Oliphant’s recent study on the death penalty’s effect on homi­cide rates pub­lished in Criminology & Public Policy found ​“no evi­dence of a deter­rent effect attrib­ut­able to death penal­ty statutes.” Oliphant first dis­cuss­es deter­rence the­o­ry, which ​“posits that pun­ish­ment, or the threat of pun­ish­ment, dis­cour­ages indi­vid­u­als from com­mit­ting crime,” and its role in cap­i­tal pun­ish­ment dis­course, where pro­po­nents of the death penal­ty have argued that the threat of the death penal­ty dis­cour­ages homi­cide, and that abo­li­tion (or a halt to the use of the death penal­ty) would lead to increased murder rates. 

The research focused on four states which imposed mora­to­ria on the death penal­ty — Illinois, New Jersey, Pennsylvania, and Washington — and exam­ined the homi­cide rates in each state in the years pre­ced­ing and fol­low­ing the state’s insti­tu­tion of a death penal­ty mora­to­ri­um. Compared to pre­dic­tions based on homi­cide rates in sim­i­lar states, none of the four saw an increase in homi­cides attrib­ut­able to the mora­to­ria, con­trary to the deter­rence argu­ment for the death penal­ty. Illinois, New Jersey, and Washington actu­al­ly had reduced homi­cide rates fol­low­ing their mora­to­ria, even con­trol­ling for oth­er influencing factors. 

While Oliphant cau­tions that each state’s results might not be gen­er­al­iz­able to all oth­er states, he con­cludes that ​“pol­i­cy mak­ers con­sid­er­ing death penal­ty mora­to­ri­ums should be aware that an analy­sis of four recent death penal­ty mora­to­ri­ums found no evi­dence to sug­gest that they led to increas­es in homi­cide. Given the grav­i­ty of cap­i­tal pun­ish­ment and the inabil­i­ty to right wrong­ful exe­cu­tions, it is crit­i­cal­ly impor­tant that pol­i­cy mak­ers weigh evi­dence of the death penalty’s capac­i­ty to deter with con­sid­er­a­tions of equi­ty, jus­tice, and fairness.”