This study focuses on a nonmonetary dimension of public policy—innovation by states in the fields of education, welfare, and civil rights. Innovation is considered equivalent to the adoption of a law by a state. From the literature on diffusion (or spread) of innovations, the explanation of user interaction is taken, and a simple model with an interaction term is constructed. The model performs fairly well when evaluated by several common criteria. The results do vary somewhat from one issue area to another; other types of supplementary analysis also indicate variation in diffusion patterns according to the issue involved. Political and economic differences among states are found to account for differences in time of adoption, and “innovativeness” is shown to be an issue- and time-specific factor.