With Circular H.S.1 1972/73, the Ministry of Education directed Ontario's secondary schools to provide an increased range of course offerings and to allow students as much freedom as possible to choose their own courses. To identify the effects of the individualized "credit system" established by this controversial circular, a number of studies were conducted during the 1972-73 school year. The study described in this report investigated how the new system was affecting student social and achievement patterns and standards for student evaluation. Intensive studies were conducted of five Ontario secondary schools, which were selected to represent contrasing degrees of H.S.1 implementation. Data were gathered from verbal and mathematical skill tests administered to year 4 students, from questionnaires completed by teachers and students in years 1-3, and from interviews with a sample of all students, teachers, and administrative personnel from the five schools. (Author/JG)