Formative and summative evaluations in education are compared, and appropriate uses of these methods in program evaluation are discussed. The main purpose of formative evaluation is to determine a level of mastery of a learning task, along with discovering any part of the task that was not mastered. In other words, formative evaluation focuses the learner and instructor on specific learning necessary to obtain mastery. Summative evaluation is aimed at a more general assessment of the extent to which educational goals have been attained over an entire course or program of study. While formative evaluation highlights areas that need improvement or remediation, the goals of summative evaluation are: (1) grading or certifying students; (2) judging the effectiveness of students' learning; and (3) comparing curricula. Formative evaluation is a short-term effort of specific content, with focus on specific abilities. Summative evaluation, a more general long-term effort, focuses on transferable abilities, often cognitive in nature. Summative evaluation occurs when it is too late to modify the process under study. Formative test results may lead to conclusions that other methods would be more effective. Ideally, educators should incorporate both types of evaluation in program development. A chart summarizes differences between the two types of evaluation. (SLD)