Ethnography may be used to inform the audience of a curriculum program with the activities of the educators and students involved. Thus the expository function of evaluation is best met by ethnography. A conceptual model developed at the Central Midwestern Regional Educational Laboratory incorporates ethnographic data and techniques into curriculum evaluation. The model uses three dimensions: data, including scale measures, questionnaire responses, and participant observation; the role of the evaluation--which is either to evaluate a completed program or to evaluate a program in progress so that the results of evaluation may be used to modify the program, which is then re-evaluated; and, the focus of investigation, which is on student, mediator, or material. The mediator is usually the classroom teacher. The model establishes the parameters of evaluation, and specifies and integrates three different approaches to evaluation. The ethnographic data may also serve as a source of new hypotheses and substantive theories. (JM)