The determinants of marital fertility in the United States, 1968-1970: inferences from a dynamic model.

Criticizing the static assumptions of previous socioeconomic and microeconomic models of marital fertility, particularly regarding the sequential and stochastic facets of family building, this paper advocates a dynamic perspective. Of particular concern is the assumption of equilibrium family size made by those who employ the static perspective. The equilibrium family size assumption implies that the parameters relating social and economic variables to fertility will be similar for all births, regardless of order. To test this assumption of constancy, a two-equation model of fertility and female employment is introduced. Contrary to the static perspective's implication of constant effects, substantial parity differences in the estimates of parameters for both equations are reported, as are several differences between blacks and whites. On the basis of this evidence, I conclude that the static decision-making framework should be replaced by a dynamic approach to marital fertility.