It also looks at cost.

Only once you look at school zones that have fewer than 60 percent of proficient or advanced students in reading do you find median prices under $600,000.

Former DCist editor-in-chief Ryan Avent can often be found doing the yeoman’s task of sorting through census data on his blog, but he dug up a couple of real gems in a recently released stack of paper: July 2009 estimates released by the U.S. Census Bureau estimate that D.C. is but a few hundred people short of crossing the 600,000 mark. The upswing would make it the fifth fastest growing “state” in the union, if…