ARTICLE IN PRESS JID: ECOEDU [m3Gdc;March 23, 2015;17:12] Economics of Education Review 000 (2015) 1–16 Contents lists available at ScienceDirect Economics of Education Review journal homepage: www.elsevier.com/locate/econedurev Review The impact of teachers’ unions on educational outcomes: What we know and what we need to learn Joshua M. Cowen a,* , Katharine O. Strunk b,1 a College of Education, Michigan State University, 116-F Erickson Hall, East Lansing, MI 48824, United States b University of Southern California, United States article info Article history: Received 6 February 2015 Revised 17 February 2015 Accepted 22 February 2015 Available online xxx JEL classification: I20 J5 J51 J58 Keywords: Economics of education Teacher unionization abstract In this paper we consider more than three decades of research on teachers’ unions in the United States. We focus on unions’ role as potential rent-seekers in the K-12 educational landscape, and specifically how teachers’ unions impact district and student outcomes. We review important methodological improvements in the identification of union impacts and the measurement of contract restrictiveness that characterize a number of recent studies. We generally find that the preponderance of empirical evidence suggests that teacher unionization and union strength are associated with increases in district expenditures and teacher salaries, particularly salaries for experienced teachers. The evidence for union-related differences in student outcomes is mixed, but suggestive of insignificant or modestly negative union effects. Taken together, these patterns are consistent with a rent-seeking hypothesis. We conclude by discussing other important union activities, most notably in the political arena, and by noting that recent changes in state laws pertaining to teachers and teacher unions may provide context for new directions in scholarship. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Teachers’ unions, perhaps more than other public sector unions, have remained controversial since their early incep- tion in the 1850s. Although teachers’ associations were origi- nally intended to advocate and provide support for members, they have evolved into highly active and influential players in local, state and national contexts. Teachers make up 26.6% of state- and local-public sector workers and are unionized at a higher rate than many other public sector workers (Sanes & Schmitt, 2014). The two major teachers’ unions, the National Education Association (NEA) and the American Federation of Teachers (AFT), have grown from just 700,000 members in 1957 to a combined membership of over 4 million educators * Corresponding author. Tel.: +1 517 355 2215. E-mail addresses: jcowen@msu.edu (J.M. Cowen), kstrunk@rossier.usc.edu (K.O. Strunk). 1 Tel.: +1 213 740 2190. and education support providers. In fact, the NEA today is the largest labor union in the United States. The two teach- ers unions spend more than any other public sector union on federal lobbying activities. 2 It is not just their size and political power that make teach- ers’ unions important for focused study. Teachers’ unions play an active role in setting school district policy through their role as collective bargaining agent for teachers in the 45 states (plus the District of Columbia) that require or per- mit teachers’ unions to collectively bargain with district ad- ministrators. The resulting collective bargaining agreements (CBAs, or contracts) regulate nearly every aspect of teachers’ work and school operations, which has led one scholar to note that union contracts are the most important policy document governing school district operations (Hill, 2006). CBAs regu- late education policy regarding teacher salaries and benefits, 2 Data retrieved February 2014 from the Center for Responsive Politics, www.opensecrets.org. http://dx.doi.org/10.1016/j.econedurev.2015.02.006 0272-7757/© 2015 Elsevier Ltd. All rights reserved. Please cite this article as: J.M. Cowen, K.O. Strunk, The impact of teachers’ unions on educational outcomes: What we know and what we need to learn, Economics of Education Review (2015), http://dx.doi.org/10.1016/j.econedurev.2015.02.006