The Effect of Direct Democracy on the Size and Diversity of State Interest Group Populations

This article studies the effect of direct democracy on the size and diversity of state interest group populations, providing an empirical test of a formal model of how access to the initiative process affects group formation and activities (Boehmke 2000). The model predicts that more groups mobilize and become active in initiative states; this prediction is confirmed by the regression analysis in this paper: direct democracy increases a state's interest group population by about 17%. With an additional assumption, I also generate and test the hypothesis that the increase is disproportionately centered among traditionally underrepresented citizen groups, relative to business and economic groups. This hypothesis is also empirically supported: citizen interest group populations are increased by 29% whereas the increase is only 12% for economic groups, suggesting that direct democracy increases diversity in interest group representation.