The housing market keeps reporting good news. Sales volumes have risen, as has new construction activity. Even real estate prices, after falling for years at a frightening pace, have begun to firm. The whole picture is a welcome change from the steep slide and stark fears of past years, and it promises, at long last, that housing will contribute going forward to the economy’s overall health, at least marginally so. But it would be a mistake to read too much into such news. The real estate sector still has much to overcome. If the recent flow of data offers reasonable assurances that the worst is over, remaining impediments will contain future gains in housing. Still, gains, even when contained, are a vast improvement over the free fall of recent years.