Hours of work equations are derived from the constrained maximization of a utility function that is not separable over time and that varies with a household's demographic structure. These equations are fitted to observations on wage rates, nonlabor income, and other variables for husbands, wives, and unmarried women. The dependence of each household's current work and consumption behavior upon its work and consumption behavior in the past is examined closely and different interpretations of the relationship are confronted with the data.

O. C. Ashenfelter, G. E. Johnson, J. H. Pencavel; Trade Unions and the Rate of Change of Money Wages in United States Manufacturing Industry12, The Review

We present a framework for measuring the joint impact of labor unions on wages, employment, and days of work. Our particular application uses county level observations to measure the impact of unionism in West Virginia coal mining from 1897 to 1938. The widespread belief is that union-nonunion wage differentials in coal mining during this period were of the order of 50 percent or more. Our estimates are substantially less. We measure negligible differences in union-nonunion employment, while, in the 1920s, operating days in unionized mines were about 25 percent below those in nonunion mines.