Representational concentration and interest community size: A population ecology interpretation

We extend Gray and Lowery's (1996) work on interest community concentration in ways that generate novel insights about several of the empirical and theoretical controversies on interest system diversity found in the literature. This explanation, which suggests that interest community diversity is an artifact arising from the distinct growth processes of the different types of interests found in the community, is tested with highly detailed and complete data on the diversity of state interest communities, demonstrating that the empirical relationship between diversity and interest system size can be replicated solely from knowledge about the density functions of interest guilds. We use these findings both to evaluate the population ecology model's interpretation of diversity and to comment on, several substantive issues raised in the larger literature on interest representation.