Quasi-experimental teacher effectiveness studies have indicated that properly designed staff development programs can lead to changes in teacher and student behavior and to gains in student achievement. Those studies involved workshop series led by nationally known scholars. Using instructors from varied backgrounds, the current study examined the extent to which the findings of prior research would generalize to contexts where experimenter effects were less likely to confound findings. Four series of the Stallings Effective Use of Time Program were analyzed for levels of teachers' classroom behavioral change. The leaders of each series were, respectively, an external consultant, university professors, local principals, and local teachers. Classroom observational data gathered before and after the four workshop series provided significant, though limited, support for the generalizability of change from such programs. The leader characteristics variable produced no significant effects, thus increasing the support for potential cost-effective use of prior teacher effectiveness quasi- experiments.