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Intended and unintended consequences

Some offenders are given short prison sentences. They tend to be people who are generally not faring well before they go to prison; they may have difficulty finding a job for instance. A short spell in prison can make them even more vulnerable. Attention therefore needs to be paid to continual supervision after the sentence. Leiden scholars draw these kinds of conclusions by researching the intended and unintended consequences of detention.

Prison Project

Although in the last 50 to 100 years many general insights have been gained about prison sentences, little detailed empirical research has been conducted into the intended and unintended consequences of prison. To find out more, criminologist Paul Nieuwbeerta and his colleagues in the Prison Project followed about 1,900 prisoners between 2010 and 2015. The participants were interviewed several times: when they were held in a remand prison, during their prison sentence and 6 and 24 months after release. They were asked about various factors that are thought to cause people to commit a crime or reoffend, such as living conditions, work, partner, physical and mental health, and norms and values.

Nieuwbeerta: ‘One thing that struck us was that prison sentences are really short. Half of the prisoners in the study came from a remand prison and therefore only had to sit out a short sentence. Furthermore, we found that many people were plagued by various social problems. They are homeless, for example, or unemployed. Often they are youths with an instable home life who have difficulty finding a job. The physical and mental health of many participants was poor. This makes research into the effect of a prison sentence difficult: this group does not fare well after detention, but they weren’t doing well before they were sent to prison in the first place.’

Suspects are held in a remand prison as they await trial, for instance. Being on remand is at least as hard as being in prison because the regime there is strict. This is because suspects of both minor and serious crimes are held together. Photo: ‘De Schie’ remand prison in Rotterdam, source: Wikipedia

Career prospects

This conclusion applies to the career prospects of prisoners, for instance. In the Prison Project, Anke Ramakers researched the prospects of prisoners before, during and after their sentence. She mentions some of the results: ‘A substantial number of the prisoners proved to have no work experience before their sentence. Those with work experience generally had an instable job history with various short-term jobs, dismissals and cash-in-hand jobs. We also looked at whether the prisoners made use of the opportunity to work during their prison sentence [prisoners can work for businesses, doing packaging work for instance, ed.] or taking courses in such areas as job skills training or cognitive behavioural therapy. Their sentence was often too short to enable them to follow such a course: to qualify for many courses, prisoners must have been sentenced to four months or more. After their release, prisoners often end up in the world of temporary jobs.’

Ramakers: ‘Our conclusion is that detention in itself does not greatly affect people’s career prospects. After their release people do not fare significantly worse on the job market than they did before. But the period of imprisonment does not appear to improve their career prospects either. Supervision after release would seem like a good option to improve their prospects, which were often not particularly good before they went into prison. Another interesting finding is that a significant number of those who did have work before they went to prison were able to return to that job after their release. This might happen more often if prisoners were encouraged and facilitated in seeking contact with former employers.’

Surprisingly enough, former inmates do not fare significantly worse on the job market than before their imprisonment.


Nieuwbeerta mentions a few surprising general conclusions about the intended and unintended consequence of a longer prison sentence. ‘A proven intended consequence of a longer prison sentence is that it deters those offenders who made the rational decision to commit a crime from committing such a crime again. In addition, a longer prison sentence also proves to have a positive effect on the unintended consequences. Ex-prisoners often lose their home, work and relationship, which increases their likelihood of reoffending, but a longer spell in prison means that you can offer anger management or job training, for instance. This increases their chances of better social conditions after detention.’

The Leiden researchers will use the results of the Prison Project for further research in the coming period. They will be able to give detailed advice on how to improve the implementation and consequences of a prison sentence.

Prison project
News article on research into life in Dutch prisons (in Dutch)


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