In recent years, some of D.C.’s once-struggling elementary schools have seen a boom in enrollment and prestige. Take Powell Elementary School in Petworth, whose enrollment has climbed from barely 200 in 2009 to 446 this year, prompting a massive expansion of the school building that’s currently underway. Similar scenes have played out elsewhere in the city, particularly in Capitol Hill.

But as those students approach middle school, the numbers start to change. Some Capitol Hill elementary schools have fifth-grade populations that are a fraction of the size of their kindergarten and first-grade counterparts. Why? Because families that have bought into the city’s elementary schools still don’t trust the neighborhood middle schools, so many switch to charters or other options as middle school approaches.

The chart above, from the Office of Revenue Analysis, shows how drastic this trend is. More than 4,000 students started kindergarten at traditional D.C. public schools in 2006. By the time that class reached sixth grade, its population was just over half its initial size. Meanwhile, the charter population doubled.

Given how recently DCPS enrollment has spiked—driven in large part by the city’s overall population boom and a growing cohort of middle-class parents who might earlier have moved to the suburbs but now feel more comfortable with D.C.’s public schools—it’s possible that the pattern will begin to change. Perhaps today’s elementary schoolers will bring their large numbers into D.C.’s middle and high schools.

But so far, we’re not seeing much evidence of that. Younger classes of elementary schoolers have followed basically the same pattern as their predecessors:

It’s too early, of course, to know where that last red trend line will head. It’s possible that middle schools in neighborhoods with increasingly popular elementary schools—say, Capitol Hill’s Eliot-Hine Middle School and Petworth’s soon-to-be-reopened MacFarland Middle School—will benefit from their feeder elementaries and start to see the same growth. But for now, DCPS enrollment still faces a sixth-grade cliff, or, as others have termed it, “sixth-grade brain drain” or “the middle school effect.”

Charts via District, Measured