The final cost estimate produced by the non-partisan CBO -- that the health care measure would cost $940 billion over 10 years, and bring down the deficit over that same time period. [Source]
The $800 billion federal stimulus bill has boosted employment by 1 million to 2.1 million and helped the economy grow about 1.5% to 3.5% larger than it would have without the stimulus, the nonpartisan Congressional Budget Office said Tuesday. [Source]
The Congressional Budget Office, a nonpartisan watchdog, forecasts that the US will post deficits in excess of a trillion dollars in each of the next 10 years. [Source]Even the more reasonable Matthew Yglesias will cite their scoring without ever questioning them.
While the CBO is supposed to be neutral, it doesn't take much thought to realize how naive that is. Since its creation in 1975 (thanks to some 1974 legislation), the CBO director's appointed by the mutual agreement of the Senate pro tempore and the Speaker of the House after considering the recommendations of their respective budget offices (though by tradition each chamber alternate this responsibility). In addition, either chamber may fire the director by resolution. So you'd think that if you're the CBO director, you have a pretty strong incentive to be partisan.
If I'm right, then when both chambers are of one party, the director should be that party as well (or at least sympathetic to it). This is somewhat easy to check. CBO directors aren't politicians and don't wear their affiliation on their sleeves, but thanks to some Googling and checking Wikipedia, I estimated the party affiliation of each director (excluding acting directors, which are covered by the white spaces). Here's the list of past CBO directors. The size of the blocks under the CBO heading is the length of that person as the director. If the director changed mid-year, I counted the full year if that person was more than halfway through the year and not in the year at all if he or she left before the halfway mark.
Even if you complain that so-and-so isn't partisan, or so-and-so isn't the party I assigned it, the correlation's strong enough that any single change doesn't change the overall pattern.
The chart above is not to be the definitive data which proves the CBO's partisanship, just an illustration that this neutrality everyone talks about is just hopeful thinking. And I'm first to admit my categorization isn't perfect. For example, the only reason I put Douglas W. Elmendorf as a Democrat is that he was a senior fellow at Brookings, which leans left if it leans any direction at all. The more important point is that of incentives: even if Elmendorf is non-partisan, that he can be fired by Democrats (and only Democrats) gives him plenty of reason not to be.