Lane Kenworthy observes that for all its flaws, the American education system really does lean against inequality:
Second, we have evidence from the natural experiment that is summer vacation. During those three months out of school, the cognitive skills of children in lower socioeconomic status (SES) households tend to stall or actually regress. Kids in high-SES households fare much better during the summer, as they’re more likely to spend it engaged in stimulating activities. In his book Intelligence and How to Get It, cognitive psychologist Richard Nisbett concludes that “much, if not most, of the gap in academic achievement between lower- and higher-SES children, in fact, is due to the greater summer slump for lower-SES children” (p. 40).
The summer vacation issue is something that middle class people tend not to think about. But when you consider it for a moment, it’s clear that there’s a real problem here. After all, it’s not as if the child development process goes on hold just because the weather’s warm. Loving parents continue to attempt to nurture their children’s growth. But parents with more time, financial resources, social capital, and know-how are going to be able to accomplish much more for their children than will low-SES parents. In a 2008 CAP paper, Melissa Lazarín examined the benefits of expanded learning time for English language learners, which seems like a particularly intuitive case of the summer vacation problem. A seven year-old whose parents are fluent English speakers doesn’t halt his English-language development just because it’s summertime. but a seven year-old growing up in a Spanish-dominant immigrant household basically does.
Or simply consider anyone whose parents fall into the surprisingly large category of illiterate adults. If you can’t read, you’re not going to read to your children. But middle class parents do read to their children—teaching them, in effect—whether or not it’s summer vacation.
For more on this I’d recommend “Summer Learning Loss: The Problem and Some Solutions” and CAP’s extensive work on expanded learning time. There are some challenges to improving educational outcomes for the underprivileged that are very complicated conceptually or politically. This one really isn’t. It costs some money, but it’s also very costly to have children grow up with subpar educations.