It is widely recognized that interest groups affect both microeconomic and macroeconomic outcomes. However, few researchers have attempted to empirically discern the factors that contribute to interest group activity. This paper provides a test of several theories of group formation in a panel...

We investigate the relationship between interest group activity and investment by analyzing an unbalanced panel of observations on 126 countries over three time periods. We find that the number of interest groups in a nation is negatively related to investment, consistent with a sclerotic effect...