Does policing help in reducing crime rates?

Those studies trying to assess the impact of policing on crime which are based on police-recorded crime figures often report a negative effect of police on property crime but no effect of police on violent crime. In a recent TILEC discussion paper, TILEC member Ben Vollaard and co-author Joseph Hamed (Dept for Innovation, Universities and Skills, UK) provide evidence that measurement error in recorded crime statistics in the UK results in underestimation of
the effect of police on violent crime. They do not find a similar estimation bias for the effect of police on property crime. Changes in the way the police record violent incidents rather than changes in reporting behavior of the public are shown to be the underlying cause of the estimation bias. This type of measurement error in police-recorded crime has been found in many countries, including the US. To address the classical chicken-and-egg problem in the relation between police and crime, the authors model the police funding formula which is used to distribute police resources across police force areas in England and Wales. By using the difference between actual police levels and police levels predicted by the funding formula, they can identify the real effect of police on crime.