By: John E. Eck

Increasing attention is being paid to the systematic review and synthesis of evaluations of large-scale, generic, crime prevention programs. The utility of these syntheses rests on the assumption that the programs are designed to work across a wide variety of contexts. But many police problem-solving efforts and situational prevention interventions are small-scale efforts specifically tailored to individual contexts. Do evaluation designs and methods applicable to generic programs apply to problem specific programs? Answering this questions requires examining the differences between propensity-based and opportunity-blocking interventions; between internal and external validity; and between the needs of practitioner evaluators and academic researchers. This paper demonstrates that in some common circumstances, weak evaluation designs may have greater utility and produce more generalizable results than very strong evaluation designs. This conclusion has important implications for evaluations of place-based opportunity blocking, and for how we draw general conclusions about what works when, and what seldom ever works.

Crime Prevention Studies, volume 14, pp 93-117