Interaction analysis, a system for observing and coding the verbal interchange between a teacher and his pupils, is used to study spontaneous teaching behavior and to help teachers modify their behavior. Trained observers classify teacher statements according to; a) acceptance of student feelings; b) use of praise and encouragement; c) acceptance of student ideas; d) use of questions; and e) use of lecture, direction, or criticism. Two additional categories relate to the verbal behavior of students and one category covers the contingency of silence or confusion in the classroom. Inferences drawn from a tabulation of the teacher's statements are discussed in a feedback session. In modifying teacher behavior through the use of interaction analysis, steps must be taken regarding: a) training of observers and participating teachers in the use of the technique; b) clarification of the participating teacher's self-development goals; c) construction of comparison situations involving a planned change of behavior and scheduling two or more observations to assess evidence of change; d) the collection of other evidence of behavior change. To reduce distortion of teacher behavior while being observed, it is suggested that: a) an observer be in the classroom only when invited; b) the status and power difference between a teacher and observer be at a minimum; and c) the feedback session follow a logical plan of inquiry. (See related document SP 007 826.) (HMD)