The effect of police on crime and arrests

Are police deterring or incapacitating criminals? 

"The BOCSAR study assessed the impact of additional police on rates of crime and arrests by exploiting a large increase in the size of the NSW Police Force in the lead up to the 2003 NSW State Election. Between 2002 and 2003 the size of the police force increased by 7.2%. This equates to an average increase of about 10 additional officers per Local Area Command."

Source: Yeong, S. (2019). NSW Bureau of Crime Statistics and Research. Available from this link.