Expert Commentary

How teachers unions affect school district spending, student achievement

We’ve gathered research that looks at the work of teachers unions, including their impact on school district spending, student achievement and teacher turnover.

Teachers holding picket signs.
Teachers with the Chicago Teachers Union hold picket signs in 2012. (Flickr/TMT-photos)

Denver public school teachers went on strike Feb. 11, for the first time in 25 years, to push for better pay. The teachers union in Oakland, California has announced plans to strike after failing to reach an agreement with the school district on higher wages, smaller class sizes and other issues. In January, teachers in Los Angeles, the nation’s second-largest school district, went on strike for the first time in 30 years to force district leaders to work with their union to address some of the same concerns.

While many educators credit their unions for helping them secure higher salaries and better working conditions, union critics accuse these organizations of hurting students by shielding low-performing and problematic teachers from disciplinary action or dismissal. At the national and state levels, teachers unions have become a powerful force, influencing both legislation and elections.  

The two main teachers unions, the American Federation of Teachers and National Education Association, are among the biggest labor organizations in the United States. Together, they represent about 5 million employees, officials from the two organizations told Journalist’s Resource. 

Below, we’ve gathered a sampling of research that offers insights into the work of teachers unions, including their impact on teacher salaries, student achievement and teacher turnover. We’ve included several studies that look specifically at collective bargaining agreements, or the written contracts that unions negotiate with districts to regulate such things as teacher evaluation, compensation, grievances, class size and job transfers.  

Toward the bottom of the page, we provide links to additional resources, including data on teacher salaries and union donations to political candidates. 



“The Impact of Teachers’ Unions on Educational Outcomes: What We Know and What We Need to Learn”
Cowen, Joshua M.; Strunk, Katharine O. Economics of Education Review, 2015. 

In this study, Joshua Cowen and Katharine O. Strunk of Michigan State University examine 30 years of research to understand how teacher unions impact district spending, teacher pay and student achievement. They find that school districts with teacher unions spend more money and they spend it on different things. “The majority of studies find that unionized districts have higher spending and specifically higher spending on teachers’ salaries, and especially salaries for veteran teachers,” the authors write.  

However, unions do not appear to help — and might actually hinder — student test scores and graduation rates. Early research suggests that students in unionized districts earn slightly higher achievement scores. But according to the authors, the most rigorous studies, which were conducted in more recent years, indicate that students in unionized districts have slightly higher dropout rates and slightly lower rates of math and reading proficiency. “It is as yet unclear the impacts of stronger unions on achievement,” they write.


“Public‐Sector Unions and the Size of Government”
Paglayan, Agustina S. American Journal of Political Science, 2018. 

This study from Agustina Paglayan, an assistant professor at the University of California, San Diego, analyzes data collected between 1959 and 1990 to determine whether unions are associated with increased education spending. Paglayan examined school district expenditures before and after states passed laws requiring districts to engage in collective bargaining with their teachers unions.  

Here’s what she found: States where districts must bargain with unions spend more than states where collective bargaining is not mandatory. However, these differences existed before the laws were enacted. “I document that in 1990, states with mandatory collective bargaining laws had more teachers per student, higher salaries, and higher per-pupil education expenditures, but I show that they already did so well before the emergence of collective bargaining rights or modern teacher unions,” Paglayan explains. 


“Labor Union Strength and the Equality of Political Representation”
Flavin, Patrick. British Journal of Political Science, 2018.  

Patrick Flavin, an associate professor of political science at Baylor University, looks at union membership and contributions to political campaigns to determine whether they help ensure that the opinions of lower-income Americans are given equal weight in the policy-making process. Flavin finds that union membership is strongly associated with equality in political representation. Political donations, however, are not. “The analysis,” he writes, “points to the conclusion that labor unions’ ability to promote more egalitarian patterns of political representation lies in their effectiveness in organizing and then mobilizing union members to political action as opposed to contributing directly to state political campaigns.” 


“When Government Subsidizes Its Own: Collective Bargaining Laws as Agents of Political Mobilization”
Flavin, Patrick; Hartney, Michael T. American Journal of Political Science, 2015.  

Flavin and Michael Hartney, an assistant professor of political science at Boston College, explain that teachers became more involved in politics toward the end of the 1960s and into the 1970s, when more than half of U.S. states started requiring school districts to engage in collective bargaining with their teachers unions. The scholars sought to determine whether collective bargaining laws actually cause teachers to become more politically active. 

A key takeaway: Teachers participated in politics at higher rates after collective bargaining laws were mandated in their states. They were more likely to say they engaged in activities such as working for a political campaign, attending a political rally or donating money to a political candidate. “In the two subsequent elections following the passage of a bargaining law in their state, and especially the third and fourth elections after the law went into effect, teachers reported a sharp increase in their rate of political participation,” the authors write. In addition, teachers who identified as union members participated at higher rates than those who did not. 


“The Myth of Unions’ Overprotection of Bad Teachers: Evidence from the District-Teacher Matched Panel Data on Teacher Turnover”
Han, Eunice S. Working paper, Labor and Worklife Program at Harvard Law School, 2015. 

For this study, Eunice Han, an assistant professor of economics at the University of Utah and senior research associate at Harvard Law School, investigates the effect of teacher unions on teacher dismissals. Her findings suggest that school districts with collective bargaining agreements are more likely to dismiss under-performing teachers who have not yet earned tenure than districts that don’t have these agreements in place. “Teachers unions raise the dismissal rate of non-tenured teachers as they bargain for higher teacher salaries, giving greater incentives for districts to sort out better teachers,” Han writes. She notes that unions do not appear to have an effect on the dismissal rate of tenured teachers. 

Han does find, however, that unions may encourage teachers to stay in the field. Her analysis indicates that teachers who work in districts where collective bargaining is allowed are less likely to quit teaching than those who work in districts that don’t negotiate with their unions.  


Collective bargaining agreements 


“The Long-run Effects of Teacher Collective Bargaining”
Lovenheim, Michael; Willén, Alexander. National Bureau of Economic Research, Working Paper No. 24782, 2018. 

This paper claims to provide the first analysis of collective bargaining laws’ effect on the long-term outcomes of students. The authors examined bargaining laws for each state and year since 1955. They paired that data with data the U.S. Census collected between 2005 and 2012 via the American Community Survey, which gathers detailed information on American adults’ education levels and employment. 

The authors find that attending all 12 years of elementary and secondary school in a state with mandatory collective bargaining laws reduced adult earnings by $799.73 dollars per year. “Across all 33 states that have a duty-to-bargain law in place, our results suggest a total loss of $199.6 billion dollars per year due to individuals having grown up in states that mandate collective bargaining between teachers’ unions and school districts,” write Michael Lovenheim, an associate professor at Cornell University, and Alexander Willén, an assistant professor at the Norwegian School of Economics. 

While overall education attainment is only marginally affected, men and women who grew up in school districts with required bargaining laws are more likely to be unemployed. Those with jobs work less per week, according to Lovenheim and Willén. “Exposure to a duty-to-bargain law while in grade school lowers the likelihood a worker is employed by between 0.9 and 1.2 percentage points,” they explain. 

Lovenheim and Willén find that the effects are larger for men as well as adults who are not white. “In particular,” the authors write, “yearly male earnings decline by $1,384 and hours worked decreases by 0.63 hours per week. We find some evidence of a small decline in educational attainment for men, who also experience a decline in wages due to growing up in a duty-to-bargain state. Among nonwhites, earnings decline by $1,986 and hours per week are reduced by 1.2.”  


“It is in the Contract: How the Policies Set in Teachers’ Unions’ Collective Bargaining Agreements Vary Across States and Districts”
Strunk, Katharine O.; et al. Educational Policy, 2018.  

Researchers looked at more than 1,000 collective bargaining agreements negotiated between school administrators or school boards and their local teachers’ unions in three states — California, Michigan and Washington — to determine how different or similar these agreements are. They looked at how contracts addressed 43 issues, including teacher pay, seniority rules, membership responsibilities, layoffs and transfers. The authors were particularly interested in whether contracts varied by district size and student households’ income levels.  

The authors analyzed 492 California contracts from the 2014-2015 academic year, 516 Michigan contracts from 2013 onward and 268 Washington contracts from the 2014-2015 academic year. They explain that “the dominant finding of this article — and the one we argue should hold the attention of the research and policymaking communities alike — is that teacher contracts do vary considerably between and within states.”  

Another key finding: In these three states, school district size is correlated with certain teacher contract provisions as well as contract length. For example, contracts in larger districts tend to include limits on maximum class sizes and are less likely to require the district to post all certificated vacancies before filling them. Contracts also tend to be much longer in larger districts. 


“Collective Bargaining and School District Test Scores: Evidence from Ohio Bargaining Agreements”
Hall, Joshua C.; Lacombe, Donald J.; Pruitt, Joylynn. Applied Economics Letters, 2017. 

This study focuses on the relationship between collective bargaining agreements and student test scores in Ohio public school districts. The researchers analyzed teacher contract provisions during the 2007-08 academic year, measuring the strength of each teacher union by the number of pages included in its bargaining agreement. The authors also looked at the percentage of ninth graders in each district who passed the state’s math proficiency exam in 2008. 

The main takeaway: In Ohio school districts, the length of a union’s collective bargaining agreement was linked to lower math scores. “It would seem that more stringent negotiations lead to less productive education production,” the authors write.  


Other resources: 


Looking for more research on teachers? Check out our collections of research on teacher misconduct, performance pay and how children benefit from having teachers of the same race.  



This photo, taken by TMT-photos and obtained from Flickr, is being used under a Creative Commons license. No changes were made.

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