The effectiveness of individually prescribed microteaching training modules in the acquisition of selected teaching behaviors is being studied in two different contexts: during the preinternship year in the Master of Arts in Teaching Program, Johns Hopkins University, and during student teaching in Teacher Education Centers, University of Maryland. It is hypothesized that the experimental (microteaching) groups (1) will acquire a significantly greater number of selected, specific teaching behaviors, (2) will have a significantly higher indirect-direct ratio, (3) will acquire a greater number of alternative teaching patterns, and (4) will make a significantly greater number of "emitted" responses. The final report will compare seven teaching performances of five trainee groups; preliminary findings have been analyzed for one comparison between 10-minute, video taped samples of teaching performance (1) of the control group (22 randomly selected interns who had one summer of student teaching but no microteaching before their internship) during the eighth and 12th weeks of their internship and (2) of a microteaching group (10 interns who had one semester of course study and microteaching before internship) on a final microteaching lesson prior to internship. Three different instruments were used for coding and scoring data before t test analysis. Findings support hypotheses 1 and 3. (JS)