The Weldon Cooper for Public Service at the University of Virginia, in charge of the state’s demographic count, has given itself a pat on the back for its ten-year projection of 2020 Virginia population. The self congratulations are probably deserved.
Weldon Cooper’s projection was only 0.27% higher than the Census Count. The actual population increase was 7.4% between 2010 and 2020. Also, projections for 90% of Virginia’s localities fell within 5% of the actual count.
Making population projections is a tricky business. Check out Shonel Sen’s discussion on the StatChat blog to get an idea of the challenge. The projections are used by a wide variety of state agencies for planning purposes, so accurate forecasts are important.