Does Punishment Deter?

Policy Backgrounders | Crime

No. 148
Monday, August 17, 1998
by Morgan O. Reynolds

The Impact of Punishment

Only after World War II did scholars begin to study the effects of deterrence. Today a large body of scholarly literature generally confirms the value of punishment in the prevention of crime.18 Students of the question have come at it from difference angles. Some simply ask if punishment deters. Others want to know which deterrent is more effective - certainty of punishment or severity of punishment.

Figure II - Cost and Social Saving for Each Additional Prisoner

General Evidence that Punishment Deters. Isaac Erhlich's 1973 study of punishment and deterrence is perhaps the most widely cited in the field.19 Using state data for 1940, 1950 and 1960, Ehrlich found that crime varied inversely with the probability of prison and the average time served.

For each 10 percent rise in a state's prison population, University of Chicago economist Steven Levitt estimated, robberies fall 7 percent, assault and burglary shrink 4 percent each, auto theft and larceny decline 3 percent each, rape falls 2 1/2 percent and murder drops 1 1/2 percent.20 On average, about 15 crimes are eliminated for each additional prisoner locked up, saving social costs estimated at $53,900 - well in excess of the $30,000 it costs annually to incarcerate a prisoner. [See Figure II.] Another study, by Llad Phillips, found that each year of prison prevented 187 crimes per year.21

"On average, about 15 crimes are eliminated for each additional prisoner locked up."

Certainty of Punishment vs. Severity of Punishment. Scholars regularly consider which provides the greater deterrent. One provocative study involved prisoners and college students. When tested, both groups responded in virtually identical terms. Prisoners could identify their financial self-interest in an experimental setting as well as students could.22 However, in their decision making, prisoners are much more sensitive to changes in certainty than in severity of punishment. In terms of real-world application, the authors of the study speculate that "long prison terms are likely to be more impressive to lawmakers than lawbreakers."23

Supporting evidence for this viewpoint comes from a National Academy of Sciences panel which estimated that a 50 percent increase in the probability of incarceration prevents about twice as much violent crime as a 50 percent increase in the average term of incarceration.24

Likelihood of punishment often tends to affect property crimes more than violent and sexual offenses. This point is borne out in a study by Itzhak Goldberg and Frederick Nold showing that in communities where more people report burglaries to the police, fewer burglaries take place.25 A tendency to report crimes has an aggregate deterrent effect on criminals because it raises expectations of punishment.

Nonetheless, severity of punishment remains crucial for deterrence. "A prompt and certain slap on the wrist," criminologist Ernest van den Haag wrote, "helps little."26 Or, as Milwaukee Judge Ralph Adam Fine wrote, "We keep our hands out of a flame because it hurt the very first time (not the second, fifth or 10th time) we touched the fire."27

To a degree, the certainty vs. severity argument is academic. As Donald Lewis wrote in 1986 after surveying the economic literature on crime, "The bulk of evidence resulting from the competent use of theory and statistics supported the existence of a deterrent effect of both imprisonment risk and longer sentences." Lewis emphasized that a substantial body of evidence is consistent with "the existence of a deterrent effect from longer sentences."28  V. K. Mathur reached similar conclusions after studying 1960 and 1970 data for U.S. cities of over 100,000 population.29

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