An integrative social identity model of collective action (SIMCA) is developed that incorporates 3 socio-psychological perspectives on collective action. Three meta-analyses synthesized a total of 182 effects of perceived injustice, efficacy, and identity on collective action (corresponding to these sociopsychological perspectives). Results showed that, in isolation, all 3 predictors had medium-sized (and causal) effects. Moreover, results showed the importance of social identity in predicting collective action by supporting SIMCA's key predictions that (a) affective injustice and politicized identity produced stronger effects than those of non-affective injustice and non-politicized identity; (b) identity predicted collective action against both incidental and structural disadvantages, whereas injustice and efficacy predicted collective action against incidental disadvantages better than against structural disadvantages; (c) all 3 predictors had unique medium-sized effects on collective action when controlling for betweenpredictor covariance; and (d) identity bridged the injustice and efficacy explanations of collective action. Results also showed more support for SIMCA than for alternative models reflecting previous attempts at theoretical integration. The authors discuss key implications for theory, practice, future research, and further integration of social and psychological perspectives on collective action.
Keywords: collective action, injustice, efficacy, social identityWhat is it that mobilizes people to participate in social protest? This has been a key question in social science from the foundation of its various disciplines, and numerous explanations have been explored. Research has examined social movements, social groups, and experimental groups, embedded in different social contexts, and studied with different methods and measures. Although qualitative reviews of this literature are abundant (e.g., Kelly & Breinlinger, 1996;Klandermans, 1997Klandermans, , 2004Marx & Wood, 1975;McPhail, 1971;Stürmer & Simon, 2004a), there is at present no quantitative research synthesis of the literature that focuses on multiple predictors of collective action and their interrelations. This is unfortunate for several reasons.First, although the literature on this topic is large and multifaceted there is substantial scope for theoretical integration (e.g., Klandermans, 1997Klandermans, , 2004. Indeed, given recent calls for greater integration in this domain, a quantitative synthesis that evaluates and integrates these theoretical advances would seem both timely and valuable. Second, a quantitative research synthesis of psychological predictors of collective action is of interest to disciplines including psychology, sociology, political science, and economics. In such a multidisciplinary arena, a key challenge is to bridge subjective (psychological) and social (structural) perspectives on when, why, and how people engage in social protest. This challenge is underlined by several recent efforts in the literature to a...