Selectively sentencing habitual offenders to longer prison terms can dramatically lower crime rates. When targeted at the most hardened habitual offenders, the benefits of lower crime rates can greatly exceed the extra costs of the longer prison terms.
These are the central findings of research by crime economist Ben Vollaard, published in the March 2013 issue of the Economic Journal. His study, which evaluates the costs and benefits of a habitual offender law adopted in the Netherlands, finds that cities that implemented the law reduced their rates of domestic burglary and theft from cars by an average of 25%. Crime fell by 40% in cities that applied the law most intensively.
Under the law, which came into force in 2001, people with more than 10 offences on their criminal record (and a history of being resistant to rehabilitative programmes) faced a two-year prison term rather than the usual few weeks. Including pre-trial detention, the terms could be as long as three years. On being caught for another offence after release, the offender could be sentenced to another enhanced prison term. Most of the offenders had a long history of offending and drug abuse.
The study compares the experiences of 30 cities that implemented the law at different times and with varying intensity. Identification of the crime-reducing effect of longer sentences is based on the fact that the criminal activities of the affected offender population were strongly tied to a specific locality.
Vollaard finds that the benefits of the law in terms of the reduced number of offences were at least twice as high as the extra costs of the enhanced prison terms. The extra costs were roughly €50,000 (£43,000) per year per offender.
But he also finds that the benefits went down rapidly with more intensive use of the law. The reason is that cities targeted the most prolific offenders first and then moved on to the somewhat less prolific offenders. Nevertheless, the benefits of the policy remained higher than the costs, even for the cities that used the law most intensively.
The overall rate of incarceration was hardly affected by the law because of the small number of offenders involved. The offenders sentenced under the law only constituted around 5% of the prison population.
Until now, there has been virtually no evidence on the crime-reducing effect of habitual offender laws. California”s ”three strikes” law has attracted the most attention from researchers, but is not representative of habitual offender laws: the law is not selective in targeting only the most prolific offenders and it merely enhances prison terms that are already very long.
”Preventing Crime through Selective Incapacitation” by Ben Vollaard is published in the March 2013 issue of the Economic Journal. Ben Vollaard is at Tilburg University in the Netherlands.

Ben Vollaard
Tilburg University | +31-6-41604444 | b.a.vollaard@uvt.nl