What does cost-benefit analysis add to decision making? Evidence from the criminal justice literature Kevin Marsh & Aaron Chalfin & John K. Roman Published online: 12 April 2008 # Springer Science + Business Media B.V. 2008 Abstract This paper asks whether undertaking a cost-benefit analysis provides additional information to policy makers as compared to an analysis solely of the effect of an intervention. A literature review identified 106 evaluations of criminal justice interventions that reported both an effect size and measures of net benefit. Data on net benefit and effect size were extracted from these studies. We found that effect size is only weakly related to net benefits. The rank order of net benefits and effect size are minimally correlated. Furthermore, we found that the two analytic methods would yield opposing policy recommendations for more than one in four interventions. These bi-variate findings are supported by the results of multivariate models. However, further research is needed to verify the accuracy of the standard errors on net benefit estimates, so these models must be interpreted with caution. Keywords Cost-benefit . Criminal justice interventions . Economic efficiency . Economic evaluation . Decision making Introduction This study assessed the contribution that cost-benefit analysis can make to public policy decision making. Specifically, it asked the following question: Does undertaking a cost-benefit analysis provide additional information to policy makers compared to an analysis solely of the effect of an intervention? J Exp Criminol (2008) 4:117–135 DOI 10.1007/s11292-008-9049-1 A. Chalfin : J. K. Roman Urban Institute, Washington, DC, USA K. Marsh (*) Matrix Knowledge Group, Epworth House, 25 City Road, London EC1Y 1AA, UK e-mail: kevin.marsh@tmkg.co.uk