Prison time is not of the essence

By Enes Al Weswasi

Enes Al Weswasi. Photo: Department of Criminology, Stockholm University

After decades of declining numbers of offenders sentenced to prison in Sweden, the trend in recent years instead conveys the opposite: the number of inmates and the average sentence length is increasing. Consequently, the Swedish prison and probation Service predicts a 40% increase in prison capacity by 2030. The influx of inmates can in part be explained by the increase of gang-related activities that Sweden is witnessing but it is also a consequence of multiple criminal policies that have increased the overall use of incarceration. This development highlights theoretical and policy implications concerning custodial penalties and if increasing prison spells are crime preventive or maybe criminogenic.

In a newly published study (Al Weswasi, Sivertsson, Bäckman & Nilsson 2022), that was presented at the NSFK Research Seminar, me and three other colleagues from the Department of Criminology, Stockholm University, examined if changes in the amount of time an inmate spends in prison affect post-release recidivism among first time incarcerated offenders. To study this effect, three policy reforms were utilized that all affected the share of a sentence that an inmate needed to serve before being early released from prison. In July 1983, the share a short-term inmate had to serve before being early release was decreased, from two-thirds the sentence, to half the sentence. This reform was repealed in July 1993, so that short-term inmates once again had to serve two-thirds of the sentence before being early released. During these reforms, long-term inmates only had to serve half of their sentence before being early released but in January 1999 a reform was enacted that increased the required share to two-thirds meaning that all inmates now had to serve two-thirds before being early released. Because these reforms either increased or decreased the share of required incarceration time before early release, the effects of both increased and decreased incarceration time on recidivism are estimated.

The study data of approximately 3 000 inmates were drawn from the convictions register maintained by the Swedish National Council for Crime Prevention (BRÅ) and cover the period 1973 to 2017. This means that we have the entire conviction histories of all cohorts born after 1957. Our outcome variable post-release recidivism is measured in three different ways: reconviction, reincarceration, and the number of crimes during follow-up (of 10 years).

The outcomes of our study show that incarceration time does not seem to affect post-release recidivism – irrespective of how recidivism was measured or if incarceration time was increased or decreased. We also measured if an effect could be found when incarceration time was increased/decreased on those who serve longer or shorter sentences but no effects could be seen among these inmates either. Although an increase in incarceration time did not seem to increase recidivism, an interpretation of these outcomes is that the overall crime-control benefits of increasing incarceration time for first-time incarcerated offenders may be questioned.

Al Weswasi, E., Sivertsson, F., Bäckman, O., Nilsson, A. Does sentence length affect the risk for criminal recidivism? A quasi-experimental study of three policy reforms in Sweden. J Exp Criminol (2022).

Enes Al Weswasi is a PhD student at The Department of Criminology, Stockholm University. His area of research is the effects of having undergone a custodial sentence and the mechanisms within a sentence that may have a rehabilitative or criminogenic effect. Email: