Note IPP n°105

Are mandatory minimum sentences an effective tool for preventing recidivism?

note 105 , IPP logo, illustration: drawing of a man's face, and hands firmly holding the bars of his jail in place of his brain
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Are mandatory minimum sentences an effective tool for preventing recidivism? Arnaud Philippe, Aurélie Ouss. March 2024. Policy brief No 105.


Adopted in August 2007 in France, the law on mandatory minimum sentences introduced harsh minimum penalties for legal recidivists, that is, individuals convicted for the second time for similar offences. The reform was followed by effects, in the sense that there was a very clear increase in the sanctions pronounced against recidivists upon its adoption. For the first time, an independent study is assessing the long-term deterrent effects of this scheme, which was repealed in 2014.

Key results

  • The law induced a sharp increase in prison sentences for recidivists (fixed sentences 50% higher, suspended sentences with probation three times higher), but no change in sentencing for repeat offenders or first-time offenders.
  • The law dit not have a deterrent effect in the short term.
  • In the medium term, individuals who received these minimum sentences recidivated less (10% lower probability), but only for offenses eligible for minimum sentences. Their likelihood of committing other offenses has not changed. Their likelihood of committing other offences has not changed.
  • People who have received minimum sentences therefore seem to be learning the letter of the law. This, coupled with a weak spread to co-offenders, has resulted in a low overall deterrent effect of the reform.

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  • Aurélie Ouss is a professor in the Department of Criminology at the University of Pennsylvania.
  • Arnaud Philippe is Professor of Economics at the University of Bristol, in the Department of Economics.

Method and data

This note is based on an analysis of the judicial trajectory of 64,000 recidivists and repeat offenders in the 4 to 6 years following their release from prison.

Reference study

Learning by Offending: How Do Criminals Learn About Criminal Law? by Arnaud Philippe, American Economic journal: Economic policy (forthcoming)

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