Arts education can close the achievement gap, according to a new study by the National Endowment for the Arts. "By nearly every indicator studied, students from low socioeconomic (SES) backgrounds with a high-arts educational experience significantly outperformed peers from low-arts, low-SES backgrounds, closing (and in some cases eliminating) the gap that often appears between low-SES students and their more advantaged peers," writes Anne O'Brien in a blog post for Learning First Alliance.

Test scores aren't the only thing that get a bump from arts education. The study found that low-SES students who are exposed to the arts are more likely to graduate from high school than their peers. Moreover, they are more likely to attend and graduate from a university.

Given the positive impact of arts education on learning outcomes, the steady decline of these programs in schools, particularly those that serve low income students, is disappointing, says O'Brien.

Drama and dance have been particularly hard hit in the wake of No Child Left Behind, according to new data from the U.S. Department of Education. Dance instruction dropped from 20 percent of schools in 1999-2000 to 3 percent in 2009-10. Drama/theater dropped from 20 percent to 4 percent.

But some question the "teach-arts-for-better-test-scores" mentality. "The real question is what do the arts teach children that other subjects can't? said education writer and professional flutist Nancy Flanagan.

She writes, "But where did we get the idea that artistic expression is less useful or important than the sciences? How did music, art, dance and drama get pushed aside in our American school curriculum? I’m not surprised that studying or listening to music has beneficial effects on learning fractions or other academic skills, but those are side effects. Kids should study music because it’s central to every human society on earth and has a vitally important role in every aspect of culture, from history to literature to media and communication studies. Music is part of what it means to be a human being."