Cost-benefit analysis examines inputs and outputs and their values for the purpose of aiding decisionmakers in effectively allocating resources. Forms of cost analysis include program cost estimates, comparative cost analysis, cost-effectiveness studies, cost-benefit analysis, and cost function studies. Selection of a particular form is determined by the nature of available information. Outputs of individual agencies of the criminal justice system are often difficult to conceptualize, although the overall objective of the system is to reduce or control crime. Cost analysis is also restricted by data inadequacies and imprecise estimates. Because of these difficulties, evaluators must choose appropriate output measures. For example, police departments can be compared on a cost-effectiveness basis by comparing costs per arrest. The evaluator's choice among the various types of cost analyses must be determined by balancing the information desired for decisionmaking against the data requirements for the desired type of analysis. The evaluator should decide whether the additional costs of a more complex analysis, such as cost-benefit analysis, will be justified in terms of the value of a better decision. Undertaking a more complicated analysis on a shaky data base may be counterproductive. A 1964 study by Sellin and Wolfgang to measure the seriousness of crime in terms of dollar value is summarized for the purpose of discussion. A list of 22 references is appended.