§ Mr. Gibb:To ask the Secretary of State for the Home Department what assessment he has made of the deterrent effect of the length of a custodial sentence. [128547]
§ Paul Goggins:It is extremely difficult to measure the deterrent effect of sentencing separately from its other effects. Apart from serving as punishment, sentences can impact on crime in a number of ways, through incapacitation, reform and rehabilitation, as well as the deterrent effect. Reconviction rates, for example, are lower for those who serve longer terms of imprisonment than those who serve shorter terms, but this reflects a number of factors and the contribution of deterrence cannot be readily isolated.
In 1999, the Home Office's Research, Development and Statistics Directorate commissioned the University of Cambridge to review all the recent research looking at the impact of sentence severity on deterrence. That study1 concluded that the limited available evidence in this area suggests that generally the connection between variations in sentence severity and deterrent effect is not direct or strong. Nevertheless the availability (and 44W severity) of punishment does appear to have a general deterrent effect for some classes of potential offenders, whose choice of whether to offend is influenced by their perception of the risks of being apprehended and punished. This suggests that known penal threats can have a deterrent effect.
1 Von Hirsch, A. Bottoms, A. Burney, E. and Wikstrom, P-O. (1999) Criminal deterrence and sentence severity; an analysis of recent research. Institute of Criminology, University of Cambridge. Hart Publishing, Oxford.