Cost-benefit analysis (CBA) is a systematic approach to examining the relative strengths and weaknesses of alternative policies, programs, or actions with the goal of choosing that alternative which maximizes societal welfare. In the context of crime and justice evaluation, CBA is used to quantify the efficiency of policies aimed at reducing or controlling crime and recidivism. Theoretically CBA is underpinned by the New Welfare economics model, which evaluates policies against the Kaldor Hicks or net benefits criterion. CBA guidelines and tools follow a structured protocol that disaggregates CBA into manageable components. A number of CBAs of developmental, correctional, and situational crime prevention studies have been undertaken. However, recent evidence provided by the “What Works Crime Reduction” study shows that economic analyses are problematic with regards to the quality of data and evaluations conducted across a number of intervention types.