Dan Drezner asks WTF? Data on the US economy are all over the map, and people he respects are wondering if the data aren’t missing important intangible things entirely, leading to a misleading picture of the economy as a whole.
Don’t look here for answers, but at least the questions are interesting.
Some insider doubt about wether the whole thing is measurable:
http://www.blogginwallstreet.com/2006/01/dark-matter.html
Some real bias according to CEPR economist Dean Baker look at the PDF!)
http://maxspeak.org/mt/archives/001964.html