Of the many ideas involved in evidence-based policing, two principles are key for law enforcement agencies: (1) applying existing knowledge about effective and fair tactics and strategies to police practices and (2) developing regular processes to assess existing practices. However, police agencies are often constrained by the time, funds, and human resources available to regularly evaluate strategies and tactics or to gather existing research about policing.

One reason for developing the Matrix is to encourage the use of “evidence-assessments,” in which agencies might compare their own tactical and deployment portfolios against what is known from evaluation research. The Matrix can provide a “workspace” to roughly assess the evidence base of agency interventions and tactics in the absence of evaluation.

In this demonstration, we provide examples on how to use the Matrix to assess an agency’s deployment portfolio. The first example listed on the left (and depicted in the illustration above) shows an example used by then Superintendent Veigas of the Derbyshire (UK) Police Service to assess whether the array of tactics used by patrol and specialized units is evidence-based. Other similar examples are also given in evidence assessments of airport security (i.e., situational crime prevention measures) and the President's Task Force on 21st Century Policing.