Housing market activity has improved in recent months, with both new and existing home sales rising in October and homebuilding activity holding on to its previous gains. This has yet to translate into better news on prices, however. In fact, the fall in the national Case-Shiller index in the third quarter and the further drop in prices on the CoreLogic index in October suggest that a renewed downward trend is developing. One lingering constraint is that many households have been shut out of the market by banks still demanding much higher credit scores than a few years ago.