COMMENTARY

by Ben Adler

Mitt Romney kicked up some controversy when he visited a Philadelphia school last Thursday. Speaking to a roundtable of teachers and education professionals, the presumptive GOP presidential nominee asserted that class size doesn't affect the quality of a student's education. Citing a study of several countries by McKinsey & Co., Romney concluded, "it's not the classroom size that's driving the success of those school systems." He added that as Massachusetts governor, he found that the best schools in the state did not necessarily have the smallest class sizes. 

Teachers at the event responded with shock and outrage, citing competing studies and their own personal experience to argue that smaller classes do indeed help students learn. The Obama campaign pounced on the political opportunity, charging that Romney's claims went "against all evidence."

But, campaign rhetoric aside, what does the evidence actually show? 

Parents tend to treat it as a given that class size matters. One of the main advantages that expensive private schools offer is smaller class sizes, which allow students to receive more attention. Teachers unions make a similar argument about the benefits of smaller classes, although their conservative opponents counter that since smaller classes mean more teachers, the unions are really just looking out for their own.

But the argument doesn't always break down neatly along partisan lines. There are education reformers in the Democratic camp who agree with Romney, most notably President Obama's own Education Secretary, Arne Duncan. As Talking Points Memo reported recently, for years Duncan has been making essentially the same case as Romney, "citing studies indicating that larger classes were not inherently detrimental." Last year, TPM added, Duncan described class size as “a sacred cow and we need to take it on.” Duncan has said that if teachers would agree to fire the worst teachers and pay the best ones more to teach larger classes, children would benefit. 

Still, that doesn't vindicate Romney. Studies of class size suggest the reality is complicated, but one crucial finding is that, while more privileged and better-performing students may not be helped much by smaller classes, kids from poor families, and those with disabilities—including learning disabilities—do appear to benefit.

In other words, the greater the needs of the student, the more class size matters. And that means that letting class sizes grow will likely hurt the most vulnerable kids.

In the U.S., the most definitive studies have shown that class size does indeed matter for some students. Here's what a Brookings Institution paper from 2011 found: 

The most influential and credible study of CSR [class size reduction] is the Student Teacher Achievement Ratio, or STAR, study which was conducted in Tennessee during the late 1980s.  Beginning with the entering kindergarteners in 1985, students and teachers were randomly assigned to a small class, with an average of 15 students, or a regular class, with an average of 22 students.... elementary school students randomly assigned to small classes outperformed their classmates who were assigned to regular classes by about 0.22 standard deviations after four years. This is equivalent to students in the smaller classes having received about 3 months more schooling than the students in the regular classes. This effect was concentrated in the first year that students participated in the program.  In addition, the positive effects of class size were largest for black students, economically disadvantaged students, and boys.

The Brookings paper also noted that teacher quality matters a great deal, so a smaller class makes more of a difference when the teacher is less experienced.

But what about that international study by McKinsey that Romney cited? Like most international studies, the McKinsey study focused on developed countries. And most developed countries, thanks to their more generous social spending, do not have nearly as much childhood poverty as the U.S. As a result, fewer kids are hurt by being in larger classes.

Even here though, the evidence is mixed. One major study, for example, found significant benefits to smaller class sizes in Greece and Iceland, a smaller benefit in Japan and Singapore, and no benefit at all in 11 other countries. 

What's the takeaway here? Class size may not matter in some cases, as long as policymakers take steps to ensure that there aren't a significant number of struggling kids who really need that one-on-one attention. And that's where Romney fails the test. That's because he also supports the draconian Paul Ryan budget that would slash spending on Medicaid, food stamps, and public housing. Class size, the evidence suggests, only doesn't matter for those kids who aren't coming in to school hungry or sick. Romney, it seems, would let class sizes increase, while seeking to slash the very programs that allow kids to flourish in school regardless of class size.

If children show up to school exhausted from spending the previous night in a homeless shelter or on the street, sick from untreated illnesses, or malnourished, personal attention from teachers will be one of the only ways to give them any shot at getting an education. And Romney would take that away from them, too. 

Ben Adler is a contributing writer for The Nation and federal policy correspondent for Next American City.