Five years after former DC Public Schools Chancellor Michelle Rhee arrived on a wave of national publicity and made headlines by firing hundreds of teachers and offering triple-digit financial incentives to the good ones who remained, D.C. has the worst state high school graduation rate in the nation. Despite having spent their entire high school careers in the Rhee-formed system, only 59 percent of the class of 2011 earned a diploma within four years, according to the U.S. Department of Education.

That 59 percent rate is much lower than the 73 percent that DCPS reported in 2010, and it's also more accurate. Last year, the Education Department adopted a standard metric for all states that tracks students all the way from ninth to 12th grades. Under the new rubric, the graduation rate is 87 percent in affluent Montgomery County, 85 percent in Fairfax County and 76 percent in Prince George's County.

D.C. public charter schools' graduation rate was 77 percent, even though more than half of all charter students live in Wards 7 and 8, which have the highest poverty rates in the city. Not only did 90 percent of seniors at Ward 7's Friendship Collegiate Academy Public Charter School graduate on time, but every one of the graduates was accepted to college -- 19 of them with football scholarships.

Some DCPS high schools -- most notably application-only Banneker, McKinley, School Without Walls and Duke Ellington -- posted outstanding graduation rates too, ranging from 91 percent to 100 percent. But their excellence was more than canceled out by Cardozo and Anacostia, where more than half of the student body dropped out before earning a diploma.

This is the result of a school system in which less than half of all high school students are proficient in math and reading. It is difficult even to fault students who drop out when, after 10 years of schooling in DCPS, they still cannot read or do math at grade level. It is an indictment of a school system that continues to spend more per pupil than any other in the country.

Chancellor Kaya Henderson, Rhee's protege, recently remarked that the more rigorous method of calculating graduation rates gives the public "a more reliable way to hold us accountable." That's exactly what city residents, from the mayor on down, must now do.