New York City has made an enormous bet on transforming its highest-need schools into community hubs, pumping hundreds of millions of dollars into more than 130 of them over the last three years.

But it’s not entirely clear what types of improvements should follow from the heavy investments in things like extra medical care, social workers and guidance counselors. Higher attendance? Academic improvements? Changes in student behavior or school culture?

John King, a former U.S. secretary of education under Barack Obama and current president and CEO of The Education Trust, recently told Chalkbeat he believes in the approach as a way of addressing the barriers to learning often caused by poverty. But he cautioned against thinking of community schools as a broader academic turnaround strategy, and worries that political leaders are treating the model as a cure-all for struggling schools.

“I think it’s a good thing for kids to have access to wraparound services — full stop,” King said. “But I don’t think those services, in and of themselves, are going to produce huge academic gains.”

In fact, he said, they could crowd out other improvement efforts. “I worry that the politics are such that some folks approach community schools like, ‘Oh, now we’re done.’ What’s your turnaround strategy? ‘We’ll do the community school.’”

King’s comments highlight the box Mayor Bill de Blasio may find himself in as he tries to persuade the public that his $386 million “Renewal” school program — which uses the community school model to stoke improvements in the city’s lowest-performing schools — is paying off.

Some educators and officials have praised the program, and the extra academic support that comes with it. But results so far have been mixed, and a recent analysis conducted in partnership with Chalkbeat found that Renewal schools did not make bigger gains in graduation rates or test scores compared with demographically similar schools that didn’t receive extra resources. (The research from other districts that have deployed the model is mixed, and shows community schools don’t necessarily show academic gains.)

Still, the city is planning this fall to significantly expand its community schools program, the largest in the country, according to city officials.

We asked King whether community schools should produce clear academic gains or if improving access to social services is enough to justify the approach. Here’s what he said:

“I think it’s a good thing for kids to have access to wraparound services — full stop. I think about kids we had at Roxbury Prep — the charter school I founded in Boston — and the fact that we happened to be located in a nursing home. So we had a lot of access to nurses and therefore we had a nurse who could administer a nebulizer to kids; we had a nebulizer at school.

And so it meant that a kid who had asthma could get a nebulizer and get asthma dealt with at school and be back in class, as opposed to another school where I worked — kids would have an asthma attack, they’d go home, they wouldn’t get treated, and they’d end up in the emergency room for that. And they may end up in the hospital for a week.

In the long run, do I think community schools would make for somewhat better academic outcomes? Yes. Lots of kids need glasses and don’t have them. I was in a community school in Cincinnati — Oyler Elementary — they have an on-site vision center where kids can get their glasses at school. That’s great. In the long run, if you can’t see the board, that’s going to be a problem. So that’s going to help kids.

But I don’t think those services, in and of themselves, are going to produce huge academic gains. I think about the Roland Fryer study on Harlem Children’s Zone. They compared the kids who had just the academic benefit of the Harlem Children’s Zone charters versus the kids who had the benefit of the services in the zone. And I think Roland Fryer would argue that the evidence was the educational experience was the thing that mattered for educational outcomes. Kind of not surprising, right?

So to me, the community schools approach can certainly help, but if the school is terrible and the kids’ learning experience is terrible, it’s not going to, in and of itself, dramatically change academic outcomes. And so I worry that the politics are such that some folks approach community schools like, ‘Oh, now we’re done.’ What’s your turnaround strategy? ‘We’ll do the community school.’ That’s maybe necessary, particularly when you’re thinking about schools with extensive needs, like one in New York where 40 percent of their kids are homeless. There’s a way in which that may be necessary, but still not sufficient for good academic outcomes.”