Research on velocity of "new" DC residents in terms of moving out of the city
The Washington Post reports ("How fast are newcomers moving out of the District? Real fast") that more than 70% of "new" DC residents as of 2004 didn't file a 2012 tax return.
But the significant rise in DC's population has occurred over the past 3 or so years and so the cohort from 2004 precedes significantly newer cohorts represented in the recent rise in demand for urban living and significant growth in the city's population.
I don't know how interesting or important this information is.