Is there no link between police numbers and crime levels?

This week in the House of Commons Policing Minister Nick Herbert was asked for his assessment of the effect of the change in police numbers on the level of crime since the last General Election.

Mr Herbert responded that the Government agreed with what the Home Affairs Committee said last year, when a report on Police financing concluded that:

"We accept that there is no simple relationship between numbers of police officers and levels of crime. The reduction in the police workforce need not inevitably lead to a rise in crime. However, the loss of posts will have an impact on the range of services that the police provide and the way in which they are provided."

Full Fact readers with long memories will remember that last year we factchecked a claim that appeared in many newspapers that a fall in police numbers would lead to a rise in crime.

They based their claim on a an assessment produced by Her Majesty's Inspectorate of Constabulary (HMIC), which in a document entitled 'Police numbers and crime rates — a rapid evidence review' found that:

"A summary of existing studies would put the elasticity of property crime in relation to police numbers at approximately -0.3 — that is, a 10 per cent increase in officers will lead to a reduction in crime of around 3 per cent (and vice versa)."

While the figure relates specifically to property crime it would suggest a link between police numbers and the crime rate can be substantiated.

However the report does mention that this conclusion isn't without its problems. For example, much of the research it considered focused on a sharp increase in police numbers rather than the impact of a decrease. As the report points out it is hard not to notice a large increase in the number of police patrols, but a reduction in patrols may go unnoticed.

There is also a problem of causality: it is entirely possible that it was an increase in crime rates that prompted an increase in police numbers rather than vice versa, which the report says many papers may have failed to compensate for.  

The HMIC report also concludes that it is too early to say whether there is a link between higher numbers of police and lower levels of crime but that:

 "there is relatively strong evidence for the potential of an effect of police numbers on crime, particularly with regard to property and other acquisitive forms of offending."

In fairness to both the Committee and Mr Herbert, neither are arguing that there is no link between police numbers and crime levels, but rather that there is no simple link, and the report by HMIC would seem to support this argument.