If the graduation rate of any urban high school system dropped 15 percent in one year, you’d expect people to get fired. But with today’s news that D.C. schools saw such a decrease in 2011 relative to the year prior, officials are applauding. Not the graduation rate, mind you—but rather how it’s calculated.

According to the D.C. State Superintendent for Education, some 58 percent of D.C. students that started in 2007-2008 graduated within four years. That’s down from the 73 percent reported in 2010, but not because students are doing worse, but rather because schools are more accurately measuring graduation rates. Under an old measure that was recently abandoned, the absolute number of graduates was counted, regardless of whether it took them more than four years to receive their diplomas.

For D.C. school officials, the drop is a good thing.

“For years, we’ve known that our graduation rates did not accurately reflect our successes and our challenges with our high school students,” said Chancellor Kaya Henderson a press release. “With the new calculations, we have a clearer understanding of the work we still need to do, and the public has a more reliable way to hold us accountable.”

So how did individuals schools do? Topping the list were the city’s four application-only high schools—Banneker, McKinley, School Without Walls and Duke Ellington—where the 2011 graduation rate ranged from 100 percent to 91.67 percent. The seven schools after that were all public charter schools, with graduation rates ranging from 91.30 percent at Washington, Math, Science & Tech to 75.44 percent at the Thurgood Marshall Public Charter School. Wilson High School topped the city’s traditional public high schools, with a rate of 73.76 percent.

Lower down the list, Cardozo High School hit 39 percent, while Anacostia High School was at 42 percent.

DCPS Graduation Rates