Direct observation of the classroom should be used to generate as well as verify hypotheses about classroom environment and activities. For example, a case study of one classroom (SP 002 697), which was compiled from field notes, discussions, and teacher's written comments, led to the concept of pupil-teacher "contracts" and to hypotheses about teacher awareness. (This method applies not only in the field of educational psychology, but also in supervision and curriculum evaluation.) During subsequent testing of hypotheses, visits to the classroom and school serve to confirm, supplement, or alter conceptions about feedback derived from other sources, such as questionnaires. The validity of classroom observation can be increased with a multimethod, multiperson, multisituation, and multivariable matrix. (A 26-item reference list is included.) (LP)