Bread and Butter or Bread and Roses? Experimental Evidence on Why Public Sector Employees Support Unions

Despite their decline, unions, and especially public unions, remain important associations. Yet we do not have a good understanding of why workers voluntarily support and join unions. We report on a field experiment conducted during a 2017 Iowa teachers union recertification election. We randomly assigned union members voting in the election to receive emails describing union benefits and measured effects on turnout effort (N=10,461). Union members were more likely to try to vote when reminded of the professional benefits — but not legal protections or political representation — their union offered. A follow-up survey identified the specific benefits that members most valued and why. In a context where union membership and support is voluntary, our findings emphasize the importance of selective professional benefits. Our results have broader implications for understanding the American labor movement and civic participation. They suggest that public-sector unions may face a tension between political activities and offering excludable workplace benefits