Zero unless they are rewriting history to claim they saw it 6 months to a year out when it was obvious to anyone who wasn't drunk on soaring home and equity prices.
The book he wrote about the coming crash was published by Wiley in February 2007, which means he must've been formed the idea some years before to have written it early enough for that publication date. A quick Google search turned up CNBC interviews with him in 2005 and 2006 about the topic.