Interest Group System Density and Diversity: A Research Update

In this paper, we replicate our 1975 and 1980 analyses of American state interest group system density and diversity with new data from 1990. The results generally support our previous findings with two important exceptions. First, contrary to all theoretical expectations and prior empirical work, including our own, we find economic wealth to be negatively associated with interest group diversity. And second, the curvi linear responsiveness of interest group density to economic size, which was already declining from 1975 to 1980, disappears in the 1990 results. This suggests that states need not drift into hyper-interest group politics as their economies expand.