Center for Problem-Oriented Policing

Appendix D: Illustration of the Use of the GE, NE, WDQ, and TNE in Lancashire, England

2008 Goldstein Award Finalist
"MOPPIN up Dodge" submitted by the Lancashire Constabulary, UK

Synopsis: A neighborhood made up largely of rental units ranks within the top 10 percent of deprived communities in England and suffers from disorderly youth, drug use, high fear of crime levels, and little community involvement. A multi-pronged analysis led to a wide array of responses, which included enforcement, situational and social crime prevention guided by crime science research. Specific tactics included standard law/ housing enforcement; innovative crime and disorder legislation; a media campaign; diversion tactics, youth outreach and a buddy system; reparation, restorative justice and ABCs; target hardening (improve lighting/fencing); modification of public places to discourage disorderly behavior; and early youth interventions. The project submission presented the actual data which was used in the following calculations:

GE = 207-110 = 97

The positive number indicates there was a decrease in crime in the target area.

NE = (207/308) – (110/318) = .326

Again, the positive number indicates there was a decrease in crime in the target area that was greater than or different from changes in the control area.

WDQ = (157/318) – (178/308) = .411
(110/318) – (207/308)

The WDQ determines the presence of displacement or diffusion in relation to changes in the treatment and control areas. Here there is a positive number, which indicates there was a diffusion effect. Because the number is less than positive one (<+1) it means that while diffusion did occur, it was not greater than the reduction achieved in the intervention area. Nonetheless, this is a very favorable finding because the response effect is amplified by the presence of diffusion.

TNE = [207(318/308) – 110] + [178(318/308) – 157] = 130.5 or 131

The total net effect gives the overall outcome of the project. The positive number here means that overall the project achieved a positive outcome and because it is fairly large the effect was pretty substantial. Another way to say this is that with the reductions achieved in the treatment area as well as with the diffusion effects and in relation to the control area, the project resulted in a reduction of approximately 131 crimes.

A successful POP project!