I reported recently on the raging debate over teacher pensions. They appear to be putting a strain on school district finances. A report by Stanford University’s Hoover Institution suggested limiting pension growth while increasing the pay of effective teachers when they are still in the classroom.

Many readers greeted that suggestion with scorn. “How dare you try to steal from our retirement!!!” one said.

Sadly, it turns out both sides of the argument are overlooking what to me is a startling fact: Only 1 in 5 teachers gets a full pension.

The experts who revealed this to me are Andrew J. Rotherham, co-founder and partner, and Chad Aldeman, senior associate partner, at Bellwether Education Partners, a national nonprofit organization focused on improving education and life outcomes for impoverished children. Aldeman is also editor of a Bellwether website, TeacherPensions.org, which examines why teacher pensions are so inadequate.

Rotherham, a former adviser in the Clinton White House and a former member of the Virginia Board of Education, has long been a leading expert on education policy. He told me more than half of people who teach never get any kind of pension. In 16 states, you have to be teaching for 10 years before you qualify.

“People say we should reward longevity, and I think we should,” he said. “But life happens to people and lots of teachers don’t teach for decades in one place, not because they don’t love teaching, or aren’t good at it, or don’t want to, but because they have to move because of their spouse’s career, military service, a sick relative, whatever.”

Rotherham said he began studying the problem 14 years ago. He realized standard teacher pensions were not designed for people who changed jobs and locations. An Urban Institute analysis showed that only after their 25th year of teaching would the lifetime value of an average teacher’s pension equal their total contributions including interest. If the teacher retired in 30 years, the big jump in value would come in only those last five years.

In an article Rotherham and Aldeman wrote for Democracy Journal, they said that in 2016 the country had 3.8 million public school teachers, “making it one of the largest professions in the United States, and by far the largest profession made up of college-educated, middle-class workers.” The size of that workforce, they said, should make teachers’ long-term financial health a national concern.

Many teachers don’t qualify for Social Security disability and retirement benefits. The Social Security Act of 1935 did not cover state workers. When states later were allowed to extend those benefits to public-sector workers, most did so, but not all.

At the moment, nearly 40 percent of teachers are not covered by Social Security. In a TeacherPensions.org article, Aldeman said most teachers without those benefits work in the District and 15 states — Alaska, California, Colorado, Connecticut, Georgia, Illinois, Kentucky, Louisiana, Maine, Massachusetts, Missouri, Nevada, Ohio, Rhode Island and Texas. Some of them get state pensions, but only if they stay in teaching long enough.

My mother taught full time in California for only a few years. Her retirement was funded by her and my father carefully investing their money. Many teachers who don’t get good pensions try to fill the gap that way.

Rotherham and Aldeman point out that federal law requires that all private-sector retirement plans allow workers to become eligible for some employer contributions within three years and become fully vested by the sixth year. Retirement strategies such as 401(k) plans may help because you don’t lose them when you move, although they vary in quality.

Any solution to the problem will require ingenuity and compassion. Every state lets teachers withdraw their own contributions to their retirement funds, but only six allow withdrawals of employer contributions. States could also allow them to enroll in Social Security, nicely portable. Cash-balance plans might work.

Rotherham offers the weary realism of a veteran participant in school debates. “Because this is education,” he told me, “staking out any position that’s not in line with one faction or another leaves you pretty homeless politically.”

An obvious first step should be to discard the assumption that any teachers you see are financially set for life because of their great pension plans.