The impact of Body Worn Video (BWV) cameras on criminal justice outcomes in domestic abuse incidents

Randomised Control Trial Status


Trial Hypothesis

1. officers will be able to collect better additional contextual information at the scene of a call out with a camera than a written statement, e.g. injuries and demeanour and deal with cases more seriously;
2. suspects because of the nature of the evidence capture using BWV will be more likely to submit an early guilty pleas; and
3. witnesses and victims are more likely to stay in the CJ process knowing that there are other sources of evidence supporting their perspective, or evidence enables victimless prosecutions.

Geographical area


Research Institution / Organisation

College of Policing

In Collaboration With

Essex Police

Contact Name

Catherine Owens

Project Start Date

January 2014

Participants - inclusion criteria

The following criteria were used that on the date of selection:
Rank: PC
Role: Response and patrol officers
Restrictions: Must be on active duty, so not on long term leave, such as long term sick or maternity leave, restricted duty or suspended.

Target Sample Size

80 officers have been allocated to the treatment group. It is expected that they will attend around 460 DA incidents a month, 180 of which will be labelled as crimes.

Study Design

​A basic randomised design comparing incidents attended by one treatment group (n=80) and to incidents attended by one control group (n=228). The 80 officers in the treatment group were allocated using a simple randomisation process, stratified by location and shift. Comparisons are to be made post-test using recorded police data and supported by qualitative research.


​The evaluation will involve a random allocation of officers to:
a) Treatment group - who wear a camera when they are on duty; or
b) Control group – who do not wear a camera.

Officers in the treatment group will be told that when attending DA incidents they must switch their BWV on, for all other incidents use is discretionary. For DA incidents the officer should record from when they are in the car, so that all information on arrival is captured. However when they arrive how they handle the situation is still at their discretion. 

For the purposes of the evaluation, if an incident is attended by multiple officers, it will be included in the treatment group sample if any officer deployed to the incident wears a camera.

Summary of Findings

The Essex Body Worn Video Trial: The impact of Body Worn Video on criminal justice outcomes of domestic abuse incidents - Full report

Date last updated

Tuesday 26 June 2018
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