RAND Europe was commissioned by the National Endowment for Science, Technology and the Arts (NESTA) to undertake a piece of exploratory research examining the types of data and information which Local Authorities draw upon to make commissioning decisions. The research focused on the field of community safety, crime and violence, and is based on twenty-three interviews with informants involved in commissioning at the local, regional, and central Government level. This research raises questions about what ‘counts’ as evidence about what works; our findings suggest that the label ‘good practice’ is often applied to services or interventions on the basis of professional judgment rather than evidence from evaluation. This, however, was rarely questioned by interviewees, who reported satisfaction with both the quantity and quality of information available about effective interventions.