Stage 1: Searching for relevant systematic reviews

The first stage was to identify systematic reviews of interventions that have been used to prevent crime. To ensure that the method used to locate the crime reduction evidence was systematic, transparent and replicable, a review protocol that outlined the procedures to be used to search for the literature was produced (Bowers et al, 2013).

This protocol was reviewed by staff at the College of Policing and a panel of external experts. To qualify for inclusion a study needed to meet two specific criteria:

  1. to be a systematic review and/or a meta-analysis and 
  2. to include a quantifiable outcome measure relating to crime.

Hence, reviews that measured impact only on (intermediate) behaviours or non-crime outcomes, such as school attendance or self-reported level of aggression, were not included.

The search for systematic reviews involved:

  1. comprehensive searches of relevant databases using predefined search terms; 
  2. assessments of whether identified studies met pre-defined inclusion criteria; and, 
  3. regular inter-rater reliability exercises to monitor levels of agreement in determining which studies did and did not meet our inclusion criteria.

This process yielded 325 unique systematic reviews that met the inclusion criteria. These were then summarised and taken on to the next stage. Further details of stage 1 and a description of the resulting evidence base can be found in Bowers et al. (2014).

Go to Stage Two of Method Statement