Homework is a perennial topic of griping among parents and students both. Just last week, Stanford researchers released a survey of students at high-performing high schools, finding that students report an average of 3-plus hours of homework per night. The conclusion? "Too much homework can negatively affect kids, especially their lives away from school, where family, friends and activities matter."

But a recent report from the Brookings Brown Center on Education casts aspersions on these findings and others like them that regularly crop up in the media (they've even produced a video summarizing media representations of homework burdens and contrasting them with their findings). The report looks at students' self-reported homework loads over the past 30 years, as tracked by the National Assessment of Educational Progress. Their bottom line? "With one exception, the homework load has remained remarkably stable since 1984."

Let's set that exception aside for one second, and look at the data on middle and high-school students. They are doing roughly the same amount of homework they did 30 years ago. Even the share of students reporting heavy homework burdens -- 2-plus hours -- has remained constant, and in fact has decreased slightly for 13-year-olds. Also notable: 17-year-olds are the most likely to blow off their assignments altogether, with 13 percent reporting this in 2012.

But the exception mentioned above is a big one: elementary school kids are doing a lot more homework than they used to. Back in 1984, only 64 percent of 9-year-olds reported having homework the night before. In 2012, that figure had risen to 78 percent. Most of that rise is from students reporting a fairly light homework load: the share saying they spent less than an hour on homework went from 41 to 57 percent. The share of 9-year-olds reporting a heavy homework load has stayed constant at about 5 percent.

The Brown Center is probably overstating its case when it concludes that "NAEP data do not support the view that the homework burden is growing, nor do they support the belief that the proportion of students with a lot of homework has increased in recent years." This may be true for teens, but the shift in homework burden for elementary students is a significant one, and one that parents of primary school-aged children are likely to feel keenly.