In an effort to bring greater conceptual richness and analytical rigor to bear on the question of postsecondary policy innovation, this study builds on the work of Hearn and Griswold (1994) by analyzing the determinants of state policy innovation in the postsecondary arena over nearly a 20-year period. Specifically, the authors employ longitudinal analysis to test the effects of: (1) postsecondary governance structure; (2) state social, economic, and political characteristics; and (3) interstate diffusion pressures on postsecondary policy innovation by state governments between the years 1981-1998. One of the primary goals of the study, therefore, is to develop and test a framework of postsecondary policy adoption that is explicitly comparative in nature; that is, one that examines how variation across state systems influences patterns of policy innovation in the postsecondary arena. (Contains 16 notes.)