Deterrence

Overview

Deterrence is prob­a­bly the most com­mon­ly expressed ratio­nale for the death penal­ty. The essence of the the­o­ry is that the threat of being exe­cut­ed in the future will be suf­fi­cient to cause a sig­nif­i­cant num­ber of peo­ple to refrain from com­mit­ting a heinous crime they had oth­er­wise planned. Deterrence is not prin­ci­pal­ly con­cerned with the pre­ven­tion of fur­ther killing by an already con­vict­ed death-penal­ty defen­dant. That falls under the top­ic of incapacitation.

Deterrence should not be con­sid­ered in a vac­u­um. The crit­i­cal ques­tion is not whether poten­tial crim­i­nals will be dis­suad­ed from killing because they would face the death penal­ty rather than no pun­ish­ment at all. Other pun­ish­ments such as life with­out parole might pro­vide equal deter­rence at far less costs and with­out the atten­dant risk of exe­cut­ing an inno­cent per­son. Whether the death penal­ty is a proven method of low­er­ing the mur­der rate has been sub­ject­ed to many stud­ies over many decades.

It is not enough to com­pare juris­dic­tions with the death penal­ty to those with­out unless the study con­trols for the many oth­er vari­ables that could affect the mur­der rate. For exam­ple, low­er unem­ploy­ment rates cor­re­late with low­er crime rates. More police involve­ment in the local com­mu­ni­ty seems to reduce crime. The death penal­ty affects only a tiny per­cent­age of even those who com­mit mur­der. Its effect is very dif­fi­cult to pin­point, and the National Academy of Sciences has con­clud­ed that past stud­ies have nei­ther proven nor dis­proven a deterrent effect.

At Issue

If the death penal­ty is not a proven deter­rent to mur­der, is it worth the exces­sive costs, risks of error, uncer­tain­ty of com­ple­tion, and oth­er prob­lems that are inher­ent to its prac­tice? On the polit­i­cal lev­el, the deter­rent val­ue of the death penal­ty is often tak­en for grant­ed with­out a care­ful exam­i­na­tion of the research or a con­sid­er­a­tion of less risky alter­na­tives. This is espe­cial­ly rel­e­vant giv­en that death penal­ty use has been declin­ing dra­mat­i­cal­ly. Most states are not car­ry­ing out any exe­cu­tions in a given year.

What DPIC Offers

DPIC has col­lect­ed many of the deter­rent stud­ies that have been con­duct­ed in the mod­ern era and has sum­ma­rized their results. It also pro­vides some of the raw data on which such stud­ies rely, such as the mur­der rate for each state in each year in the mod­ern era, along with the num­ber of exe­cu­tions and death sen­tences for each state in the same periods.