Abstract
The main aim of this study is to develop a practical, easily applicable collective action scale with its empirically revealed psychometric properties, which can be used in collective action studies in Turkey. The study was conducted with a total of 505 students from various universities. Collective Action Scale (CAS), consists of a total of nine items including various protest behaviours and social media activities. The data were analysed appropriate methods. First of all a factor analysis with Direct Oblimin rotation has shown that CAS had two sub-factors. These sub factors were named as "actions that impose legal responsibility on the individual" and "actions that do not impose legal responsibility on the individual" consistent with the content of items. It was also found that internal reliability of scale was satisfying. In addition, Functions of Identity Scale was taken as a criterion to test the criterion validity of CAS. And the relations between subscales and total scale scores of both scales were found to be significant.

Keywords: Collective Action, Identity, Protest, Collective Action Scale