Betsy DeVos’ favorite education policy keeps looking worse. Last week, the Education Department, which she runs, released a careful study of the District of Columbia’s use of school vouchers, which she supports. The results were not good.

Students using vouchers to attend a private school did worse on math and reading than similar students in public school, the study found. It comes after other studies, in Ohio and elsewhere, have also shown weak results for vouchers.

To channel President Donald Trump: Who knew that education could be so complicated?

The question for DeVos is whether she’s an ideologue committed to prior beliefs regardless of facts or someone who has an open mind. But that question doesn’t apply only to DeVos. It also applies to all of us trying to think about education, including her critics. And the results from Washington are important partly because they defy easy ideological conclusions.

Before diving into those results, I want to make two broader points. First, education isn’t just another issue. It is the most powerful force for accelerating economic growth, reducing poverty and lifting middle-class living standards. Well-educated adults earn much more, live longer and are happier than poorly educated adults. When researchers try to tease out whether education does much to cause these benefits, the answer appears to be yes.

Second, the highly charged debate over education often lapses into misleading caricature. On one side of the caricature are defenders of traditional public schools, who believe in generous funding, small class sizes and teacher training. On the other are so-called reformers, who believe in vouchers, charter schools and standardized tests.

Unfortunately, this caricature mixes several ideas that do not necessarily go together. In particular, it conflates vouchers (coupons that let parents use their tax dollars for private schools) with charter schools (public schools that operate outside the usual bureaucracy).

Hardcore reformers, like DeVos, support vouchers and charters. Hard-core traditionalists oppose both. The rest of us should distinguish between them, because their results differ.

Unlike most voucher programs, many charter-school systems are subject to rigorous evaluation and oversight. Local officials decide which charters can open and expand. Officials don’t get every decision right, but they are able to evaluate schools based on student progress and surveys of teachers and families.

As a result, many charters have flourished, especially in places where traditional schools have struggled. This evidence comes from top academic researchers, studying a variety of places, including Washington, Boston, Denver, New Orleans, New York, Florida and Texas. The anecdotes about failed charters are real, but they’re not the norm.

It’s an argument for a political compromise: fewer vouchers, more charters.

If you’re a progressive, I realize that this compromise may make you squeamish. Progressives often prefer to spend more on traditional schools — which are still crucial — and to trust them.

But I would encourage you to look at the full evidence with an open mind. Charters have the potential to help a lot of poor children in the immediate future, and it’s hard to think of a more important progressive goal.

As for DeVos, I hope she is similarly open to new facts. It seems a reasonable expectation for somebody whose title is secretary of education.

— David Leonhardt is a columnist 
for The New York Times.