Wage Differentials across Labor Markets and Workers: Does Cost of Living Matter?

Wage differential studies rarely account for interarea differences in cost of living, owing both to data limitations and theoretical ambiguity. This study develops a price index for 185 metropolitan areas comprising about 70% of the U.S. labor force. Current Population Survey data for 1985-95 and data on site-specific amenities are used to estimate earnings differentials based on nominal wages, wages fully adjusted for measured cost of living, and a simple approximation of "real" wages with partial adjustment for price-level differences. Dispersion in approximate real wages across 185 labor markets and differentials by region and city size are substantially lower than dispersion in nominal or full adjustment wages. Estimates of racial and ethnic differentials display moderate sensitivity to choice of a wage measure, whereas other standard differentials do not. Both nominal wages and wages fully adjusted for cost of living may provide misleading estimates of real wage differentials. Absent data on interarea prices and amenities, researchers should include detailed controls for region and city size in nominal wage equations. Copyright 1999 by Oxford University Press.