In 2013, for the first time, a majority of public-school students in this country—51 percent, to be precise—fell below the federal government’s low-income cutoff, meaning they were eligible for a free or subsidized school lunch. It was a powerful symbolic moment—an inescapable reminder that the challenge of teaching low-income children has become the central issue in American education.
The truth, as many American teachers know firsthand, is that low-income children can be harder to educate than children from more-comfortable backgrounds. Educators often struggle to motivate them, to calm them down, to connect with them. This doesn’t mean they’re impossible to teach, of course; plenty of kids who grow up in poverty are thriving in the classroom. But two decades of national attention have done little or nothing to close the achievement gap between poor students and their better-off peers...