The effects of patrol dosage on crimes and on calls for service in night time economy hotspots

Randomised Control Trial Status


Trial Hypothesis

​To establish if it would be possible and viable to deliver a comprehensive full experiment in the future which would be capable of delivering statistically significant outcomes. The experiment will be based on Koper’s (1995) findings which suggest that there is an optimum level of hot spot patrol dosage in crime and disorder hot spots and on a recent similar experiment in Belfast, Northern Ireland (Goddard, 2013).


The proposal will explore the following question – when focusing on traditional highly visible preventative patrol at a tactical level, what type of patrol dosage has the most effective impact on preventing crime and disorder within a night time economy environment? Further exploration will focus on whether differing levels of patrol dosage have varying impacts on the effectiveness of preventative hotspot patrolling and if so what is the optimal dosage to be delivered. This hypothesis will be explored in comparison to current Merseyside police night time economy, high crime area ‘Operation City Plan’ policing tactics.

Geographical area

​Liverpool City Centre.

Research Institution / Organisation

University of Cambridge

Project Start Date

April 2016

Participants - inclusion criteria

​10 hotspots have been paired together so they can then be separated into treatment and control groups. This randomised Block design has been found to be effective for small studies. The hot spots were paired based on similar number of reported night time economy crimes. It was necessary to put the hot spots into pairs based on the crime levels so it would allow comparisons to be drawn between treatment and control groups when analysing the results at the conclusion of the trial.

Target Sample Size

​10 hotspots. 6 weekend period experiment between the hours of 000 - 0400 Saturday and Sunday.


Treatment Hot spots

These five randomly chosen hot spots received the manipulated patrol dosage of up to 15 minutes. One patrol crew consisting of four officers, one sergeant and three constables, in a marked police vehicle will visit each of the five treatment hot spots. The officers will be instructed to get out at each hot spot and patrol the hot spot as normal, engaging with the public and dealing with any incidents as they occur.

As the trial will run from 00:00-04:00 hours each night, this will theoretically give each of the five treatment hot spots up to one hour total dosage with a maximum of 15 minutes every hour, a total of 60 minutes over the 4 hours. However it is anticipated that such matters as travelling between hot spots, comfort breaks for the officers and dealing with unforeseen circumstances would impact on this time. To counter this issue, a compliance time has been factored in allowing 10 minutes in each hour which would then leave each hot spot with a total of 50 minutes dosage time across each 4 hour period, a total of 400 minutes dosage for the entire trial of 12 nights.

Control Hot spots

These five randomly chosen hot spots will receive the normal style of policing as per the usual City Plan operation. This will consist of a combination of high visibility foot / static patrol, licensing visits and stationary police vehicles with officers on board.

Outcome Measures

As this proposal relates to a Phase 1 test it is accepted that the outcome analysis will not provide statistically significant results. However two primary outcomes measures have been identified for analysis:

  1. A comparison of the number of night time economy area defined crimes and calls for service occurring between the treatment and control hot spots during the period of the experiment; 
  2. A comparison of the number of night time economy area defined crimes and calls for service that occurred during the experiment compared to the same six week period in the previous year in both the treatment and control hotspots.

Summary of Findings

​Not available

Date last updated

Tuesday 26 June 2018
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