Although student enrollments in cooperative education constitute only about 8 percent of all high school students, about half of all high schools provide such opportunities. In practically all co-op programs, the employer ensures supervision, on-the-job learning, and evaluations that will influence students' grades; coordinators have released time to visit job sites; and each student has a written plan. A 20 percent drop in enrollments has been noted from the late 1970s to the late 1980s. Cooperative education programs vary widely, in terms of work schedules, how much work experience is provided, and whether work assignments begin in grade 10, 11, or 12. Some successful programs include the following: a health academy; an occupational cluster approach, integrating academic and vocational instruction; a tech prep program; an off-site occupational program; a capstone experience; an academic track for co-op students; a program with high admissions standards; and a reengineered 1913 program. Although little well-structured evaluation has been conducted, available data show higher wages, higher employment, and satisfied employers. Recommendations for improvement are as follows: more careful student selection; better placement of students in jobs; more emphasis on developing a "training sponsor" at each employer site; better use of training agreements; better training plans; regular visits to the worksite by teacher coordinators; better student evaluation; structural changes in curriculum; and better use of advisory committees. (YLB)