Following a brief consideration of the meanings of the terms "measurement" and "understanding," the first section of this yearbook is devoted to the theoretical aspects of understanding in elementary and secondary school students, including the importance of teaching for understanding, the nature of understanding, and nine general principles applicable to the evaluation of understanding. Presented in the second section are various methods which may be used to evaluate or measure student understandings in the subject areas of social sciences, science, elementary school mathematics, secondary school mathematics, language arts, fine arts, health education, physical education, home economics, agriculture, technical education, and industrial arts. Individual authors define understanding as they believe it applies to their subject matter specialty, usually in terms of cognitive, affective, and psychomotor goals and objectives. Examples are then given of different methods used to measure student understandings specific to the stated goals and objectives for each subject matter area. These measures include pencil-paper multiple-choice tests, observations, discussions, interviews, debates, rating scales, and essay tests among others. (JN)