What was the first scientifically engineered social experiment to test the impact of the use of arrest upon crime?

The first scientifically engineered social experiment to test the impact of the use of arrest upon crime was the Kansas City Preventive Patrol Experiment conducted in the early 1970s. The study aimed to determine if traditional routine police patrols had an impact on crime rates. The results showed that the presence or absence of patrol had little impact on crime.