Using a modified typewriter interaction analysis system, an observer is able to record specific teacher-pupil behaviors as they interact in an instructional setting and distinguish accurately and comprehensively the cause and effect relationship. The system has the capability to distinguish patterns of behavior between different teachers in such a manner that objective analyses can be made with regard to their individual competence. Further improvement of the system has eliminated two limitations found in using the modified typewriter as the sole recorder of transcational data--the conversion of the typewriter data to computer form and the development of a duration of time measurement. The solution devised is a microcomputer system called TICOR (Time Interval and Categorical Observation Recorder) consisting of an alpha-numeric computer terminal keyboard with standard typewriter key layout plus extra keys for entering data, controlling the computer, and providing access to a larger computer. The system allows the researcher to identify teacher stimuli being used to reinforce correct responses, remediate an incorrect response, or facilitate a response to a no response. These rate, sequence, and duration investigation techniques facilitate the study of effective instructional strategies and teacher-pupil behavior. (MB)