Evaluation of police Stop and Search training

Randomised Control Trial Status


Trial Hypothesis

  • Trained officers would have greater knowledge and feel more prepared for stop and search 

  • Trained officers would have attitudes more favourable to good practice in police-public interactions 

  • Trained officers would say they will behave in line with training standards on stop and search decision making and practice 

  • Trained officers’ practice would be more professional and effective

Geographical area

Six pilot forces were involved:

  • British Transport Police 

  • Cleveland Police

  • Greater Manchester Police 

  • Metropolitan Police Service (four Operational Command Units) 

  • Sussex Police

  • Thames Valley Police

Research Institution / Organisation

College of Policing

In Collaboration With

British Transport Police; Greater Manchester Police; Thames Valley Police; Sussex Police; Metropolitan Police; Cleveland Police

Contact Name

Dr Paul Quinton

Project Start Date

January 2015

Participants - inclusion criteria

Serving police officers who were:

  • in operational roles likely to carry out stop and search (e.g. response and neighbourhood officers)

  • available for training and ordinary duties during the evaluation period 

  • regular users of stop and search in 2014/15.

Target Sample Size

The total sample size was 1,323. This equated to approximately 220 participants in each pilot force:

  • 110 were randomly assigned to the treatment group

  • 110 to the control group

Study Design

The randomised controlled trial used a stratified parallel-groups design, with officer-level randomisation (see infographic of study design).  

The study included

  • an impact evaluation (carried out with the Research Advisory Service) that examined the effect of the pilot training, comparing the treatment and control groups post-test (stop and search data was compared pre- and post-test)

  • a process evaluation (carried out with RAND Europe) that examined the nature and quality of implementation in the pilot forces.


The pilot training consisting of:

  • a pre-read and knowledge check

  • a one-day face-to-face classroom session designed and delivered locally by the pilot forces based on Guidance for Trainers produced by the College

The intended focus of the pilot training was: 

  • practical knowledge of the law and decision-making 

  • unconscious bias 

  • procedural justice

Outcome Measures

Primary outcomes:

  • Officers’ knowledge (online survey)

  • Officers attitudes (online survey)

  • Officers’ anticipated behaviours in written scenarios (online survey)

Secondary outcomes:

  • Arrest rates from recorded searches (police data) 

  • The quality of recorded grounds for searches (blind-coded police records)

Monitored data (direction of change was not hypothesised)

  • The number of recorded searches 

  • The ethnic profile of recorded searches

Summary of Findings

The impact of the pilot was mixed overall. The pilot training had some small positive effects on officers’ knowledge, attitudes and anticipated behaviours immediately after the training was delivered. Some of these effects were sustained at a three-month follow-up. No effects were found on recorded stop and search practices (ie, the quality of written grounds for search or arrest rates). Substantial variation was found in training delivered by the pilot forces, although this was possibly because the trainer guidance was not sufficiently prescriptive.
Link to infographic?

Date last updated

Monday 25 June 2018
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