In this guide the logic of product evaluation is described in a framework that is meant to be general and adaptable to all kinds of evaluations. Evaluators should consider using the logic and methods of product evaluation when (1) the purpose of the evaluation is to aid evaluators in making a decision about purchases; (2) a comprehensive assessment of a product or program is important, and omitted information might be critical; and (3) the evaluation is inherently comparative or summative in nature. A product evaluation checklist is presented and discussed. Major considerations on the checklist include examining the needs of and resources available for the consumer, looking at the range of possible products, studying the products in the light of needs and resources, and, through synthesis and summary, determining the best buy. Included in the discussion of each item on the checklist are specific questions, illustrative examples of how to apply the checklist, and warnings about ways to go wrong. (RM)