Three types of educational evaluation--student learning, summative, and formative--are identified and described. Major emphasis is placed upon formative evaluation, which takes place over a period of time and is performed by professors rather than external evaluators or judges. Four possible targets for formative evaluations are: course content and organization; teacher roles; program evaluation; and assessment of special projects or innovations. Any formative evaluation program should be flexible, well directed, and confidentially conducted. The author describes a seven-step evaluation system used at McGill University between 1976 and 1978, and documents an actual case study of one professor's evaluation done in this system. Another formative evaluation system recommended for classroom performance techniques is the Teaching Improvement Process, developed by the University of Massachusetts. Every evaluation system should be subjected to periodic systematic evaluations. The key to a flexible formative evaluation system lies with the honesty of professors themselves, and a commitment to providing excellent education within a wide range of individual styles, subject areas and class types. (DC)