This paper investigates married women’s hours worked disaggregated by the husband’s wage decile. In the United States, this pattern has changed from downward sloping to hump shaped. We show that this development can be explained within a standard household model of labor supply when taking into account trends in assortative mating. A quantitative analysis of our model shows that female wage growth and decreasing fertility are primarily responsible for the overall increase in wives’ hours since the 1970s. The fact that the most pronounced increases are observed for wives married to high-wage men is a result of trends in assortative mating.

Conventional estimates of Frisch labor supply elasticities are biased in the presence of borrowing constraints. We develop an incomplete-markets model with two-earner households and derive a new estimation approach for the Frisch elasticity that yields unbiased estimates even in samples that include borrowing-constrained households. Our approach exploits that the strength of the estimation bias depends on individuals’ relative contribution to household earnings. It takes the form of a simple interaction term model with minimum data requirements. Using Panel Study of Income Dynamics data, we estimate Frisch elasticities of about 0.7 for men and rather homogeneous Frisch elasticities across the population.