Stability of Marital and Cohabiting Unions following a First Birth

Lawrence L. Wu, University of Wisconsin at Madison
Kelly A. Musick, University of Southern California

This paper investigates factors that might account for the apparent greater instability of cohabiting unions, relative to marital unions, during the period following a first birth. We hypothesize that some of this observed gross differential will reflect preexisting differences between cohabiting and married couples. For example, union stability is known to vary with duration, age, and educational attainment, with women in marital unions tending to have first births at later durations, older ages, and higher levels of educational attainment than women in cohabiting unions. Similarly, dissolution risks will be higher if a birth was unplanned or conceived prior to the start of the union, characteristics that also vary substantially by type of union. Our analyses model the effects of such observable factors using the 1995 NSFG and continuous-time hazard models. Particular attention is given to the role of multiple "clocks," including age, union duration, and duration since first birth.