In order to provide detailed descriptions of instructors' activities in courses taught by individualized instruction and to identify some of the factors responsible for variations in those activities, records were made of instructor behavior in two computer-managed Navy courses. Within each course, jobs differed considerably in kinds and patterns of activities and total demands on the instructor. Most of the specialized jobs in one course had nominal parallels in the other, but the activities observed in these parallel jobs were quite different. Most instructors spent the major part of their time in brief, relatively routine interactions; complex tutorial interactions were rare. Findings suggest that differences in course design affect demands on the instructor and that systematic tradeoffs have not always been made between such demands and training effectiveness. It is recommended that a single set of student-instructor ratios not be used to compute instructor authorizations for all such courses and that instructor training courses avoid creating unrealistic expectations of actual job performance. Since instructor roles vary so widely, considerable caution should be exercised in selecting a common core curriculum for such courses. (Author/LMM)