Simultaneity in the Timing of Marriage, Cohabitation, and Non-Marital Fertility

The process by which families in the United States are formed has changed dramatically in the later part of this century. There have been large increases in the age at first marriage and the age at which individuals begin childbearing. Further, the linkage between marriage and childbearing has weakened, with a relatively large number of children being born outside of marriage. Concurrent with these changes, there has been a dramatic increase in the rate at which individuals choose to enter a non-marital cohabitation. In this paper the authors provide a unified approach to the determinants of family formation by specifically accounting for the interrelationship of these processes. The authors' primary purpose is to examine what influences how long individuals wait to begin a relationship, either a formal marriage or a less formal non-marital cohabitation, and, prior to the commencement of a formal marriage, the determinants of non-marital childbearing. Further, and importantly, the authors examine how these decisions are related to each other. By using data that contains information about non-marital cohabitation, we explicitly model the relationship between cohabitation and other family formation decisions, a relatively new area of study due to the advent of datasets that contain explicit information about these types of relationships. By using methods that allow for the simultaneous estimation of related hazard processes the authors find evidence that these processes are interrelated. Controlling for the endogeneity of these decisions, the authors document the impact of each family formation component on the others.