Traditional formative evaluation of computer assisted instruction (CAI) products has focused on assessing learner achievement of objectives and the inferential use of this information to make revisions. A more comprehensive approach to formative evaluation includes traditional learner achievement assessment but adds assessments of the development process and of the product itself. Formative evaluation should begin well in advance of a trial product being ready for learner tryout. As soon as goals are set, instructional analyses carried out, or learner characteristics considered, formative evaluation of the decisions made and processes followed should be begun by a development team and continued throughout the development process. Additionally, the product should be examined to ensure that it includes characteristics and features consistent with learning theory and appropriate to the content being taught. The proposed outcome-oriented, product-oriented, and process-oriented approach to evaluation uses learners as a source of evaluation information, but relies as well on content and instructional development experts. Together, the three perspectives provide a comprehensive approach to the development of effective and efficient CAI materials. (15 references) (Author/DB)