Teaching, while rewarding, is one of the most stressful occupations in the U.S., and many teachers experience serious emotional and mental problems related to school stress. The COVID-19 pandemic exacerbated this phenomenon as teachers adapted to challenging working environments and navigated frequent technical difficulties in new online platforms, all while dealing with health concerns during in-person instruction.

Stress is the most common reason for leaving teaching early, and it is also associated with job absenteeism and poor teacher performance, negatively impacting student outcomes. As more schools face increased teacher turnover rates and intensified teacher shortages, it is essential to investigate what influences teachers’ job-related stress.

A key factor that can help reduce teacher stress: teachers’ unions. That’s according to findings in our new paper, which relies on nationally representative data in pre-pandemic periods that allow us to examine the impact of teachers’ unions on teacher stress.

We first compare the stress level of union teachers with that of nonunion counterparts, using various metrics to measure the strength of teachers’ unions. We control for various teacher characteristics (gender, race/ethnicity, education, experience, charter and secondary school indicators), district features (K-12 student enrollment, percent of students in free/reduced-price lunch programs, racial/ethnic composition of students, urbanism, district revenue, and living costs), and other characteristics, like cultural and political beliefs, that may be common for teachers in the same school district.

We find that teachers’ unions are negatively associated with teacher stress: the stress index of teachers in districts with collective bargaining (CB) agreements is .07 lower than that of teachers in districts with no union agreement, a statistically significant difference equal to about 14% of the standard deviation of the teacher stress index. Teachers in districts with higher union density also report lower stress than those in districts with lower union density, and union-member teachers show significantly lower levels of stress relative to non-member teachers.

We then examine the effect of the 2010-2011 anti-union laws in Idaho, Indiana, Tennessee, and Wisconsin on teacher stress, comparing how their teachers fared relative to teachers in other states that did not experience such legal changes. We expected that, if teachers’ unions indeed reduce teacher stress, we should observe that the institutional changes that weakened teachers’ unions in these four states raised teacher stress. The data do show that the new anti-union state legislation significantly increased teacher stress, and the magnitude of these negative impacts was greater for teachers who were male, more experienced and qualified, in secondary schools, and teaching STEM subjects.

How do unions reduce teacher stress? They raise teacher compensation and improve working conditions, which may contribute to lowered stress. Unsurprisingly, we find that higher teacher salary and shorter working hours are also associated with lower levels of stress, but even after controlling for these key factors, the negative effect of teachers’ unions on stress still remains statistically significant. This suggests that unions’ positive influence on teacher pay and working conditions plays a role but is not the only mechanism through which unions reduce teacher stress.

The positive union effect on teacher stress may be driven by unions’ role as “teacher voice.” Teachers’ unions provide more supportive leadership relationships, improved school climate, advocacy for professional development, and increased teacher morale. Because of these, the unions also correlate with teachers’ overall well-being, a critical pillar of teachers’ stress and their mental health.

In policies to improve the workplace for our teachers, policymakers should seriously consider teachers’ mental well-being. Our study suggests that, given their essential role in reducing teacher stress, teachers’ unions can provide members with more assistance in managing excess stress and burnout by offering additional support, counseling, and other in-depth services.