Rates of out-of-wedlock births in the US have increased over the past three decades and rates of cohabitation among unwed parents have risen. Consequently, unwed parenthood is decreasingly synonymous with single parenthood. As we focus more attention on unwed parents, their living arrangements, and relationships, it is becoming clear that cohabitation is an ambiguous concept that is difficult to measure. In this study, we use the Fragile Families and Child Wellbeing data to document how sensitive cohabitation estimates can be to various sources of information and we demonstrate that relationships among unwed parents fall along a continuum, from marriage-like cohabitation at one extreme to parents who have no contact at all with one another at the other. The results underscore the limitations of using binary measures of cohabitation to characterize parent relationships.
