The guide briefly presents some of the issues involved in evaluating substance abuse prevention programs, such as selecting factors and program outcomes and instruments, judging the quality of instruments, considering the level in intervention in selecting instruments, options in data collection, determining instrument appropriateness for various target populations, and some cautions for evaluators of prevention programs. The guide than provides specific examples of evaluation instruments in detail. The guide focuses more on youth than adults and on individual and family-level factors rather than environmental factors. Each evaluation instrument discussed in this guide is accompanied by examples of studies in which it was used, information on obtaining copies of the instrument, evidence of its usefulness, and other relevant information. Evidence of the usefulness of an instrument includes an established link between what the instrument measures and some aspect of substance abuse behavior; an appraisal of the degree to which the instrument measures what it was designed to measure; and an appraisal of the degree of interrelatedness among the items and the degree to which the instrument provides consistent results from one evaluator to another and from one time to another. 73 references, an index of instruments, and appended directories of measurement instruments