The effects of Computer-Assisted Teacher Training System (CATTS) feedback in a preservice special education teacher training program are discussed. It is explained that a series of studies were conducted to test the efficacy of CATTS feedback in effecting teacher trainees' acquisition and performance of specific teaching skills. Chapter 1 presents the goals and objectives of the project, an overview of the project (pilot procedures, descrimination training, laboratory classroom design, trainee evaluation), and describes both the organization of the CATTS project and an overview of CATTS itself (teaching station, observation coding station, analysis-encoding station). Chapter 2 deals with the two observation systems used for feedback of teacher and student behaviors to trainees, COG-STRAT (focused on teacher and student cognitive styles of interaction) and MAN-STRAT (focused on student on- and off-task behavior and strategies of teacher management of student behavior), and discusses such areas as observer training and evaluation of observer competencies. Such aspects of project organization and implementation as teacher education laboratory classrooms, implementation procedures (teaching and coding), scheduling observation and teachers, and the effects of feedback on trainee behaviors are studied in chapter 3. Chapter 4 summarizes the results of the study which revealed that all trainees significantly increased their rate of criterion performance as a function of CATTS feedback. The summary and conclusions of the project are presented in the final chapter. (BD)