Emphasize shared identity, injustice, and empowerment to motivate supporters to action. This paper analyzed data from 182 prior studies on a range of social movements around the world and integrated past theories of social movement participation into a unified framework, the Social Identity Model of Collective Action (SIMCA). People were more likely to be interested in and take action on a cause as a result of three elements: their social group was experiencing injustice towards it, they more strongly identified with that group, and/or they felt that acting together could have an impact (that is, a sense of collective efficacy). The influence of injustice was stronger when it was emotionally felt, not merely intellectually understood; and identity was more potent when it was politicized—that is, linked to an organization, movement, or broader social analysis. Of the three elements, identity was the most reliable and appeared to also influence the other two, so may be the most important for organizers to focus on. (Also see our practical guide for integrating SIMCA into climate engagement programs)

In the studies analyzed, typical wording of questionnaires to assess these three elements included:

—Injustice: “I think the way we are treated by [out-group] is unfair” and “I feel angry because . . . .”

—Collective efficacy: “To what extent do you think that this [collective action] will increase chances of the government changing their plans?” and “I think that together we can change [the group-related problem].”

—Identity: “I identify with/feel connected to/ feel strong ties with [group X]”, “I see myself as/define myself as a member of [group X].”