Welcome!
I appreciate Bernice's observation that we should be leveraging all available information to draw conclusions about the market. The repeat sales methodology used by Case-Shiller and OFHEO has its merits, most notably that it better controls for period to period changes in the type of homes sold as well as controlling for significant changes in quality and/or size. But as Bernice highlighted, the weighting applied by Case-Shiller can cause distortions. In particular I am concerned that the greater weights they apply to shorter interval sales means that they are also weighting foreclosed bank owned properties more heavily in their indices. That could be a major source of the more negative view of the markets they cover. See the note I wrote last month at http://www.housingintelligence.com/economics/s-p-case-shiller-home-price-indices-may-be-more-negative-due-to-foreclo-2.html.