In the article you can read here, we have a good example of why academic economists, even those with highly recognizable names like Mankiw and Krugman, are usually viewed as egg heads who can be safely disregarded in serious policy discussions.
Who really cares what someone's statistical analysis purports to show (unit roots, of all things) when all of history speaks so loudly about what fosters economic prosperity and human well being? History also speaks loudly about what stifles economic prosperity and human well being. We really don't need unit root analysis to point the way.
Who is it that really doesn't understand why the decade of the 90s was the most prosperous in recorded history? Who is it that thinks taxing income away from whoever earned it and giving it to people who did not earn it promotes economic prosperity? People like BHO who think "spreading the wealth" is the answer evidently haven't studied much history.
The recession the world is now experiencing will begin to abate when the Fed quits trying to save the financial necks of the wealthiest people on the planet and when the Congress quits passing laws that commit the U.S. Treasury to spend beyond what Congress is willing to tax from current tax payers.
As I've told my students, if it takes sophisticated statistical analysis to discern something, then whatever it is that's discerned couldn't be particularly important.