The Saint Clair County Teachers' Institute (Evanston, Illinois) plans and implements a 1-day inservice for 3,000 teachers (grades K-12) each year. The committee in charge of planning and implementing the inservice is composed of two co-chairpersons (each an administrator from a local school district), representatives from the regional superintendent's office, and representatives from Southern Illinois University at Carbondale. Functions of the committee include: (1) making an analysis of objective evaluation data collected from the previous year's institute; (2) deciding on speakers and booking them; (3) holding group meetings with district representatives to solicit advice; (4) seeking proposals from teachers who have an instructional technique or specific program they feel would be worthwhile; (5) making final selections about the format for the institute; and (6) printing the final program. The functional cycle of the model is an on-going process which varies yearly in composition and program focus, while returning to the cooperative development theme from year to year. A unique element of the model is the cooperative element between the university, the public schools, and the intermediate state agency, which ensures that no one group controls the committee. (JM)