Interest Group Survival: Shared Interests Versus Competition for Resources

Abstract

Population ecology theory on interest group populations is examined to determine the implications\nfor group membership levels in the states. Using the assumptions of the competitive exclusion principle,\nit is hypothesized that relatively new interest groups should not directly compete for space, but\nshould instead have a positive influence on each other's membership levels. A group's membership\nlevel should also be a function of space, energy, and political mobilization factors. Multiple regression\nanalysis is applied to a fifty-state data set using the membership levels of five gay and lesbian interest\ngroups as dependent variables. The hypotheses are confirmed—interest groups avoid direct competition\nfor space by adapting into different issue niches. The results of these findings for a population\necology theory of interest groups are discussed along with directions for future research.