Download PDF here: Grippa Impact Evaluation

The Grippa clip is designed to provide a secure fixing on which to anchor bags by hooking them onto the underside of tables or chairs. We hypothesised that usage of the Grippa clips would reduce opportunities for bag theft (thereby reducing bag theft levels) through increasing the effort and risk on the part of offenders attempting to steal (or dip from) anchored bags.

The original aim of this project was to assess the impact of the Grippa clips on bag theft levels using a quasi-experimental design across 27 pubs of the same chain. Briefly, we identified (in collaboration with our business partner) 27 pubs to participate in the project. These were chosen to represent a range of barroom settings and because they were spread throughout London.

The pubs were then analysed and ranked using an amalgam of bag theft levels between 2005/06, seating capacity and the presence (and level) of crime prevention measures more generally (for a detailed description see Bowers and Sidebottom, Grippa Evaluation Research Design: Matching Action and Control Sites). Next, each pub was assigned a matched pub on the basis of the above variables, generating 13 matched pairs and 1 remainder. One member of each pub couplet was then assigned to one of two conditions: action (to receive the Grippa clips) or control (not to receive the Grippa clips). The business collaborator had made the choices for the ‘action’ group pubs. The intended research design was that the 13 action bars would each receive the intervention. Impact would then be assessed on two levels: first, an aggregate comparison of bag theft levels across all action versus all control pubs before and after intervention; second, a comparison within each matched pair before and after intervention. We expected that implementation of the Grippa clips at the action sites would be associated with a significant reduction in bag theft levels compared to the control sites.