Union Organizing as a Mobilizing Strategy: The Impact of Social Identity and Transformational Leadership on the Collectivism of Union Members Christina Cregan, Timothy Bartram and Pauline Stanton Abstract This article investigates the effect of union organizing as a mobilizing strategy on the collectivism of union members. We examine the impact of a worker’s social identification with fellow members and the transformational leadership qualities of the local union representative. We employ regression analysis with tests of mediation to analyse the survey responses of c. 1,000 rank and file members of a major professional union, collected in July 2004 during a mobi- lization campaign. Social identification and transformational leadership were associated with members’ union loyalty and willingness to work for the union. Social identification acted as a mediating variable in both cases. 1. Introduction There are two different perspectives on union organizing. At one level, it is held to be a cost-effective, decentralized recruitment strategy, brought about by person-to-person contact at the workplace (Bronfenbrenner and Juravich 1998). At a deeper level, it is viewed as a mobilizing strategy (Cregan 2005). This article investigates organizing as a mobilizing strategy. The aim of a mobilizing strategy is to change the group ‘from being a passive collection of individuals to an active participant in public life’ (Tilly 1978: 69). A union conducts this strategy by means of a mobilization campaign. It encourages its members to engage in on-site struggles alongside other members under the Christina Cregan is at the University of Melbourne. Timothy Bartram is at La Trobe University. Pauline Stanton is at Victoria University. British Journal of Industrial Relations doi: 10.1111/j.1467-8543.2009.00733.x 47:4 December 2009 0007–1080 pp. 701–722 © Blackwell Publishing Ltd/London School of Economics 2009. Published by Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.