This article by John Aziz illustrates why I do not trust economists like Paul Krugman, Brad DeLong, and a few others.
If you read their op-eds or non-academic articles you notice one theme (now, in your most solemn, mechanical yet snobbish voice (with nasal sounds, throat clearings, and heavy exhalations through the nose)), increase government spending on...insert any project you or your ill-informed drinking partner, next door neighbor, etc can think of.
These economists will say anything to get the government to spend more money. There is never a reason to spend less, never a reason to limit the power of labor over consumers. Perhaps my least favorite attribute these individuals possess is their sense that no one on earth is smart...at anything...ever, except for them. I used to think that about myself...when I was three.