The effects of instructional guides and wait-time feedback upon the classroom interaction of 40 middle school science teachers were investigated in a prior study. The experimental nature of that study produced an artificial situation involving little personal contact between teacher-participants and the research staff. Therefore, a subsample of 10 teachers cooperated in a follow-up study. After a workshop, weekly tape recordings of the participants' classes were analyzed. Discussions with the teachers were held concerning effectiveness. Since only strengths and successes were emphasized, the process was labeled "supportive intervention." Over the 4-week duration of the study, important changes in teacher-student interaction were observed. Teachers extended their wait-times to the 3 second minimum. There was an increase in student-student interaction and in length of student responses. Teachers asked greater numbers of divergent and evaluative types of questions indicative of higher levels of cognitive discourse in the classroom. Finally, the teachers responded in a highly favorable manner to the suggestions provided by members of the research team. It appears that monitoring wait-time using an electronic device accompanied by supportive intervention does provide an avenue for the improvement of teaching skills. (JN)