This report can be read solely as an introduction to program evaluation for the program manager, funder, and the evaluator, or it can be read as a precursor to the specific evaluation reports on delinquency-prevention counseling programs. Several evaluation research models are briefly described, and problems that arise when a quasi-experimental evaluation model is applied to operational programs are considered. Practical guidelines on how to initiate the evaluation of operational programs are presented. Guidelines are provided for how to conduct an assessment of the evaluability of a program (a type of feasibility study) and the type of information system needed for a program which will facilitate efficient program monitoring and evaluation. The main issues and conclusions of the report are summarized in the final section, and the implications of some of these general issues for the evaluation of juvenile delinquency programs are considered. The report concludes that the quasi-experimental design is inappropriate for evaluating an operational social service program, since the results obtained are often misleading and uninformative. A nonexperimental type of evaluation is recommended. Such an evaluation would be concerned with assessing the efficiency and effectiveness of the program by identifying the process of operation, determining the adequacy of the process of operation relative to the theoretical or conceptual expectations for the program, and assessing all possible attitudinal and behavioral effects of the program on clients, community, and staff. Eighteen references are listed.