Longer sentences not necessarily a deterrent for repeat offenders

Francesco Drago, Roberto Galbiati, Pietro Vertova , Mon, 07/30/2007



Among the many factors that influence the decision to commit a crime, public law and sanctioning activity play a crucial role. As a result, one of the first tasks for researchers is understanding how criminals react to an increase in expected punishment. The theory of deterrence suggests that a marginal increase in expected sanctions, other things being the same, reduces the propensity to commit a crime. The authors of DP6401 test the theory in a natural experiment and found that among their dataset in Italy an additional month of expected punishment reduces the propensity to recommit a crime by 1.24%. However in the case of repeat offenders, other results emerge which somehow contradict the common view of deterrence.

It is very challenging to observe in reality the effects of a variation in expected punishment, so the authors get around the problem by exploiting the natural experiment provided by the Collective Clemency Bill passed by the Italian Parliament in July 2006. The law provided an immediate three-year reduction in detention for all inmates who had committed a crime before May 2nd 2006. It also stated that if a former prisoner recommits a crime within 5 years following release from prison, they will be required to serve the previously suspended sentence in addition to the one given for the new crime. By using a dataset from the Italian Department of Prison Administration, which included 25813 individuals, the authors calculate that an additional month of expected punishment reduces the propensity to recommit a crime by 1.24%, which supports the general deterrence hypothesis.

The data collected also allows the authors to investigate other crucial issues on deterrence such as understanding how previous sanctions affect the behavioural response to expected punishment. The results show that having experienced longer prison spells, instead of strengthening the sensitivity to the threat of sanctions, weakens the deterrent power of an increase in expected sentences. This evidence is hard to reconcile with the deterrence theory according to which a stronger experience of punishment should increase the behavioural response to future expected sanctions.

DP6401 The Deterrent Effects of Prison: Evidence from a Natural Experiment

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URL:  http://www.cepr.org/pubs/new-dps/dplist.asp?dpno=6401.asp

Topics:  Politics and economics

Tags:  crime, deterrence, natural experiment, recidivism


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