Density dependence in corporative systems: Development of the population of Danish patient groups (1901–2011)

Abstract

This article tests the density dependence theory on the population of Danish patient groups from 1901 to 2011. The theory states that the formation of interest groups can be explained by the number of groups in the population. The density dependence theory is a population theory, and these have successfully been applied to interest group populations in pluralist systems such as the American. However, they have only rarely been applied to corporative systems. As there are important differences between pluralist and corporative systems regarding how interest groups are integrated in the policy process, the interest group populations can be expected to develop in different ways. Therefore, the article explores whether and how population theories work in corporative systems by testing the density dependence theory on the population of Danish patient groups. The article conducts a graphical and a statistical analysis on a new and comprehensive data set with founding and disbanding years for all Danish patient groups from 1901 to 2011. The findings support the expectations of the theory as the density of the population has a positive and curvilinear effect on the founding rate. However, they also indicate that corporative structures may suppress the population mechanisms that are often found to drive the development of interest group populations in pluralist systems. This suggests that population theories can also be applied to corporative systems and that they can contribute to answer the much discussed question about interest group formation.