The Political Economy of Group Membership

Despite its normative importance, the question of why people join interest groups remains open. It has certainly provoked a wealth of theoretical attention. Regrettably, however, it has inspired only a handful of empirical tests. The introduction of this article places the empirical debate into its normative context. The first section develops a rational model of individual evaluations of group membership, focusing upon the effect of changing personal circumstances—preferences, needs, resources, insecurity, and information—on the calculus. In particular, the theory predicts responsiveness to political or collective benefits in threatening times. Analyses of aggregate changes over time in membership in the Farm Bureau, the League of Women Voters, and the Home Builders, reported in the second section, bear the model out. Finally, the conclusion takes on the complementary question of group supply, sketching a theory of group mobilization that emphasizes subsidization.