Lazear of "Scoring" of Legislation

Ed Lazear has an op-ed in the WSJ today concerning Congress' requiring the CBO to "score" legislation for economic growth.  To this point, the CBO has not done that on the grounds it wants to maintain an unbiased position. But, as Lazear points out, to not consider the effects on growth is to bias things in favor of passing legislation.  He offers several reasons why scoring is a good idea, and how it can be done while maintaining objectivity.