Part of a series on implementing competency-based education, this monograph discusses some diagnostic and prescriptive techniques which can be used in the day-to-day management of performance learning to determine which students need remediation or enrichment. Using analogies from detective work, the monograph suggests ways of assessing students' interest, self-concept, basic skills, and problem-solving abilities to gain clues about who needs additional attention. Several potential problems, or "alleged crimes against the student, occupational program, or occupational teacher," are then discussed to illustrate the most and least effective uses of these informal student assessments. The monograph goes on to discuss the value of "expert testimony," that is, formal measurements, such as Canfield and Lafferty's Learning Style Inventory, the Cloze procedure, SMOG assessment of reading level, math and communication tests, and professional opinions. The monograph concludes with a list of ways instructors can provide both enrichment and remediation, including the use of instructional modules, optional learning experiences, peer tutors, and reward systems to encourage the development of basic and problem-solving skills. A three-item reading list is included. (AYC)