The project was designed to assess the effects of full-credit semestering, half-credit semestering, and trimestering on the intellectual, social, and emotional growth of students in selected secondary schools in Ontario. The research focused on four major areas--the utilization of instructional time, interpersonal relationships, student achievement, and student motivation. The random samples of semestered schools consisted of seven full-credit, three half-credit, and one trimester. These schools were matched with 11 nonsemestered control schools along four variables--school size, size of community, certification of teachers, and median years of teaching experience of the staff. The major findings were that there was more variety in classroom methodology in full-credit schools than in nonsemestered schools, interpersonal relationships between students and teachers were more postitive in all types of semesters than in nonsemester schools and semestering appeared to increase the motivation of some student groups but not of others. (Author/IRT)