Modeling the Structure of Collective Action1 This material is based upon work supported by the National Science Foundation under Grant No. 0352517. The authors are equal contributors to this article.

We propose an improved theoretical approach to the rich variety of collective action now present in public life. Toward this end, we advance a conception of collective action as communicative in nature, and offer a two-dimensional model of collective action space, comprising dimensions for (a) the mode of interpersonal interaction and (b) the mode of engagement that shapes interaction. We illustrate the perspective by describing the location of a variety of contemporary collective action groups within it and by an explication of the space that reveals its utility for making sense of modern collective action efforts. Specifically, we apply the collective action space to illustrate the changing presence of collective action groups over time, deviations in collective action groups through changes in size, shape, and location, and variations in the experiences and motivations of people engaged in collective action efforts. Finally, we show how our communicative approach to collective action can integrate the insights of several theoretical traditions, including collective action theory, social capital theory, and aspects of organization theory.