See for yourself: http://www.igmchicago.org/surveys/the-cbo. And here is the information on the survey and panel:
This panel explores the extent to which economists agree or disagree on major public policy issues. To assess such beliefs we assembled this panel of expert economists. Statistics teaches that a sample of (say) 40 opinions will be adequate to reflect a broader population if the sample is representative of that population.
To that end, our panel was chosen to include distinguished experts with a keen interest in public policy from the major areas of economics, to be geographically diverse, and to include Democrats, Republicans and Independents as well as older and younger scholars. The panel members are all senior faculty at the most elite research universities in the United States. The panel includes Nobel Laureates, John Bates Clark Medalists, fellows of the Econometric society, past Presidents of both the American Economics Association and American Finance Association, past Democratic and Republican members of the President's Council of Economics, and past and current editors of the leading journals in the profession. This selection process has the advantage of not only providing a set of panelists whose names will be familiar to other economists and the media, but also delivers a group with impeccable qualifications to speak on public policy matters.
And these economists understand the task. In contrast, politicians who don't understand the task put little credibility on CBO forecasts. I don't understand the dichotomy other than politicians are notoriously partisan and therefore prone to saying whatever and behaving however to accomplish their goals.
Here is a screenshot: