In the spring of 2018, thousands of public school teachers walked out of their classrooms in a half-dozen states, protesting low salaries, rising class sizes and cuts to school budgets that have prompted most teachers to buy their own classroom supplies.

Additional strikes followed in 2019 in Los Angeles, Denver and Oakland.

While these walkouts, which enjoyed much public support, were about more than teacher pay, stagnant teacher salaries were central issues.

And political leaders have taken notice. For example, presidential hopeful Sen. Kamala Harris, a Democrat from California, has made boosting teacher salaries a part of her campaign. Her plan would allocate US$315 billion in federal funding over the next decade to increase pay for public school teachers and reward state and local governments for raising pay even higher, with the goal of eventually boosting teacher pay by an average of $13,500 per person. The proposal, which has been hailed as “the largest investment in teachers in American history” and criticized as a pitch for teacher union endorsements, would be paid for by as-yet unspecified increases in the estate tax.

From my standpoint as an expert on educational leadership and policy and as former assistant state superintendent for research and policy in the Michigan Department of Education, I see teachers as the most important resource in schools. Teachers’ impact on students persists into adulthood. Recruiting and retaining high-quality teachers in the nation’s public schools requires good working conditions, including competent and supportive leadership and a collegial environment. But pay matters.

Teacher salaries decline over time

Classroom teaching has never been a path to riches and, perhaps more than other professionals, teachers view their work more as a calling than as a way to make a good living. Still, teaching must compete with other occupations for talent. So how does teacher pay compare with the pay of other professions that require a similar education? By this comparison, teacher pay has been eroding for decades.

According to an Economic Policy Institute study, the teacher “wage penalty” – how much less teachers make than comparable workers – grew from 5.5% in 1979 to a record 18.7% in 2017.

Teacher wage gaps vary widely from state to state, but in no state does teacher pay equal or exceed pay for other college graduates. And it’s no coincidence that the four states with the largest gaps – Arizona, North Carolina, Oklahoma and Colorado – saw teacher protests in 2018.

In some states, teacher salaries have been so low that teachers have qualified for public assistance.

Fair comparisons?

How can teachers’ earnings be compared to those of non-teachers when teachers get summers off? The answer: Compare weekly wages. For example, a public school teacher in the U.S. with a bachelor’s degree earned an average of $980 per week between 2013 and 2017, while a comparable non-teaching college graduate averaged $1,326.

Some may argue that teachers, on average, work fewer hours per week than other college graduates. However, a leading teachers’ union says that teachers often work longer than their contracted work day.

What about teacher benefits? Instead of pay raises, are school districts giving their teachers generous benefit packages? No. While teacher benefits have accounted for a rising share of their total compensation as salaries have stalled and constitute a bigger share as compared with other professionals, this “benefit advantage” only partially offsets the teacher wage penalty.

Even teacher pension plans, often criticized as overly generous and costly to taxpayers, are now found to be inadequate in many states. In Massachusetts, for instance, teacher contributions to pensions plans will actually exceed their benefits no matter how long they stay in teaching.

In 39 states, the average teacher salary declined 2010 and 2016 when you take inflation into account. And these declines were not the result of teacher turnover, with retiring and relatively well-paid baby boomers being replaced by entry-level millennials. A 2018 Brookings study found that teachers were more qualified in 2016 than in 2007. Teachers were older and more educated, with greater proportions holding master’s and doctoral degrees, the Brookings study found.

The pay gap gives rise to teacher shortages. These shortages do not show up as actual vacancies or empty classrooms. Rather, they appear as underqualified teachers – that is, more positions filled by teachers lacking full credentials and holding only temporary or “emergency” licenses. Shortages in math and science have been a chronic problem for public schools, as non-teaching options have been much more lucrative for candidates in these fields.

Solving the teacher shortage problem, which afflicts every state to varying degrees, will require more than boosting teacher pay across the board. It will also take improving teachers’ working conditions, giving them more manageable class sizes and adding more support staff, such as psychologists, social workers, nurses and librarians. It will also take safe, well-maintained facilities and skilled principals who create the kind of school environments that make teachers want to stay.

Michael Addonizio does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.