A user-centered educational product evaluation model for the prepublication and postpublication assessment of materials designed for medical and dental education is presented. The model has four components: the author, user, evaluator, and publisher. It is dynamic, reactive, and interactive, with feedback from each component providing input to regenerate the process. Three general approaches to product evaluation based on this model, for the formative and summative evaluation of printed material are described. Examples are given which illustrate the developmental nature of these educational products and their subsequent modifications, based on feedback from field tests, reviews, and experimental studies. (Author)