Methodological problems in the use of participant observers.
A multiple baseline design across observed students and teachers was used to investigate the relationship between observations by participant observers and changes in the behavior of those observed ("observee" reactivity) and the observers (observer-mediator reactivity). Two teachers recorded consecutively the appropriate student verbalizations of four students and two teachers recorded the inappropriate student verbalizations of four students. Independent observers simultaneously recorded student verbalizations (appropriate and inappropriate) as well as teacher behaviors (positive, negative, and instruction) throughout all phases of the study. The results substantiated the prediction of "observee" reactivity and observer-mediator reactivity in one of four classrooms. The results of the present study suggest that in some instances, observations by participant observers may result in changes in the behavior of those being observed ("observee" reactivity) and/or the observers (observer-mediator reactivity).