Interest groups' decisions to join alliances or work alone

Theory: The benefits of coalitional advocacy in a crowded group environment, and the organization maintenance costs imposed on groups that seek to work as part of alliances are used to develop a model of organized interests' decisions to join alliances or work alone. Hypotheses: Organizations estimate whether an alliance is likely to improve their chances for success relative to working alone. The forces that affect this estimate derive from the context of the policy issue, organizations' knowledge of their potential allies, and, in a less direct way, particular institutional features of the group. Balanced against this estimate will be a group's concern for maintaining a distinct identity in the interest group and political communities. Methods: A probit analysis of interest groups' decisions to join coalitions or work alone is supplemented by information obtained through interviews with representatives of organized interests. Results: When a group's interest in an issue is narrow, and when a group's potential allies signal that they have little to contribute to a collective advocacy campaign, the costs of joining an alliance will likely outweigh any benefits that may accrue. But when organizations perceived to be "pivotal" to success are members of an alliance, and when groups represent expressive interests or perceive a strong organized opposition, the benefits of coalition appear substantial.