Documented are the activities of the Modeling Panel of the Graduate Medical Education National Advisory Committee (GMENAC) charged with three fundamental tasks: (1) to estimate physician manpower requirements for the year 1990 in each of 23 specialty areas; (2) to project physician supply for 1990 in each of these areas; and (3) based upon comparison of projected requirements and supply, to make recommendations concerning graduate medical education to balance projected supply and requirements. Part I offers an introduction and overview of GMENAC's project. Part II describes the "adjusted needs-based model" and the process of estimating its parameters using delphi panels. Part III summarizes the requirements estimates for each specialty. Part IV discusses supply projections, including a description of the "GME Model," a model of the graduate medical education adopted by GMENAC. Part V discusses the disparity between supply and requirements and makes recommendations for the future direction of graduate medical education. Among the recommendations cited are: no new allopathic or osteopathic medical schools should be established beyond those with first-year students in place in 1980-1981; the ability to read, write and speak English should remain a requirement for all alien physicians; and in view of the projected oversupply of physicians, the need to train non-physician health care providers at current rates should be studied. Members of the Graduate Medical Education Advisory Committee Model Panel and the Physician Specialty Delphi Panels are listed, and tabular statistical data and summaries are included. (Author/LC)