Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
A variance components model explains wage dispersion with a specific version of generalized least squares. The estimation preserves individual data while examining the influence of union penetration on dispersion in both the union and nonunion sectors. Controlling for both individual and industry characteristics and for the endogeneity of wages, union penetration correlates strongly with reduced dispersion in the union sector but not in the nonunion sector. A decomposition reveals the relative importance of the influences of union penetration and of union membership. Copyright 1990 by MIT Press.