Two experiments were completed to determine whether providing classroom teachers with feedback would result in changes in both teacher and student behavior. The first experiment was designed to extend the validity of an earlier investigation by Moore et al. (1974) through replication with a new teacher population and a larger sample of male teachers. The second experiment was designed to test whether teaching effectiveness would be increased if appropriate feedback involved with generating instructional sequences appropriate for individual learners was given. In the first experiment, teachers received feedback related to their ability to control their teaching behavior and their ability to apply a theoretically based rationale in the resolution of learner problems. The experimental teachers demonstrated greater control of their teaching behavior as evidenced by the low discrepancy between their ratings of the need for intervention and their satisfaction of that need. Teachers in experiment two received feedback associated with their abilities to (1) engage in diagnostic procedures when a student incorrectly answered a question and (2) utilize appropriate diagnostic sequences to resolve the problem. There were significant differences in the direction of the experimental group, indicating that (1) experimental teachers engaged in diagnosis more often; (2) they conceptualized and employed more appropriate processes for diagnosis; and (3) their students correctly answered more previously missed items than did participants in the control group. In summary, the study demonstrated the importance of conceptually appropriate feedback in bringing about changes in teacher behavior. (MB)