Female earnings and the divorce rate: a simultaneous equations model

Economists have contributed a great deal of research, both theoretical and empirical, to the study of marital formation and dissolution. Many empirical examinations of marriage and divorce rates exist based on Becker's seminal contributions to the literature. All of these divorce studies are single equation models, with female earnings assumed exogenous. As discussed by Becker (1981), however, causality may run in the opposite direction as well: the divorce rate may influence female earnings. This paper estimates a simultaneous equations model in which divorce rates and female earnings are the jointly endogenous variables. Data are by state, for 1960, 1970, 1980 and 1990. The state-wide divorce rate equation is an extension of Waters and Ressler (1999), and the specification of a state-wide earnings equation follows standard human capital theory. The specification of joint endogeneity between female earnings and the divorce rate allows valid inferences to be made regarding the effect of female earnings on divorce for the first time. Most previous single equation studies of divorce have found that increases in female earnings significantly increase divorce rates. A simultaneous equations model will allow inferences to be made regarding the possibility of joint determination, which may cause a reevaluation of previous results.