Principal reduction to ease negative equity situations may have a lot of positive effects for homeowners, but recent research suggests it may have little impact on worker mobility. A forthcoming working paper by Sam Schulhofer-Wohl, of the Federal Reserve Bank of Minneapolis, contends that research showing underwater borrowers are 33 percent less likely to move to better employment markets is flawed because it ignores key data. In an analysis of Census Bureau housing data, Schulhofer-Wohl reached the opposite conclusion, that underwater borrowers are more likely to move, suggesting that principal...