Compare methods

	Collective Action Tendency Measurement (SIMCA)	Social Identity Political Measurement
Field	Political Psychology	Political Psychology
Family	Process / pipeline	Process / pipeline
Year of origin	2008	2015
Originator	Martijn van Zomeren, Tom Postmes & Russell Spears	Leonie Huddy, Lilliana Mason & Lene Aaroe
Type	Self-report multi-construct measure	Self-report identity scale
Seminal source	van Zomeren, M., Postmes, T., & Spears, R. (2008). Toward an integrative social identity model of collective action: A quantitative research synthesis of three socio-psychological perspectives. Psychological Bulletin, 134(4), 504-535.	Huddy, L., Mason, L., & Aaroe, L. (2015). Expressive partisanship: Campaign involvement, political emotion, and partisan identity. American Political Science Review, 109(1), 1-17.
Aliases	SIMCA, Collective Action Scale, Protest Intention Measure	Political Social Identity Scale, Partisan Social Identity Measure, Expressive Partisanship Scale
Related	4	4
Summary	Collective action tendency measurement, organized by the Social Identity Model of Collective Action (SIMCA; van Zomeren, Postmes and Spears, 2008), assesses the psychological predictors of willingness to engage in protest and group-based political action: perceived injustice (especially group-based anger), group efficacy, and politicized social identity. SIMCA integrates these three traditions into a structural model in which identity drives action both directly and through injustice and efficacy.	Social identity measurement in political behavior applies social identity theory (Tajfel & Turner, 1979) to political groups, treating partisanship, ideology, or movement membership as a social identity rather than a mere instrumental affiliation. Huddy, Mason and Aaroe (2015) adapted Mael and Tetlock-style identity items into a partisan social-identity scale that measures expressive, emotionally charged group attachment and predicts campaign activity and political emotion better than issue agreement.