Congressional Budget Office Predictions and the Truth

Below, Corrections has taken nominal GDP growth predictions from 2000-2011 from the CBO and plotted them against the truth (click to enlarge). The CBO doesn't seem to systematically overpredict or underpredict one-year ahead: of ten one-year-ahead predictions, six are over, four are under. (And it's hard to fault more than one year ahead given the time period we're looking at).

Corrections also offers the same graph but with future years included (click to enlarge).