Socio-economic differentials in family formation in Norway 1987-2001

Kari Skrede, Statistics Norway
Ane Seierstad, Statistics Norway
Kenneth Aarskaug Wiik, Statistics Norway

The analysis is based on register data on family status and individual characteristics of cohorts of parental couples with their first (common) child born in the 1987 - 2001 period. The main data source is register data selecting all children born in a given year (t), who also are born as first common child of their parents. We use logistic regression analysis to explore the effects of sociodemographic characteristics of the parents on the probabilities that the parents were respectively married or cohabiting by the beginning of t+1. We model a selection process in two stages: First we include the total population of parental couples in the analysis of the probability that the couple was married at the beginning of the year t +1. Secondly, we include the “rest- population” - all non- married couples - in the analysis of the probability that the couple was cohabiting at the beginning of year t+1. The findings indicate considerable similarities in the relative effects of the socio-demographic variables for the two selection processes. The relative effects of parents' socio-economic characteristics were stronger for the probability of marriage than for cohabitation for most of the variables. However, when we include interaction effects of education and income with period, the differences in relative effects of socio-economic characteristics between married and cohabiting parents decreased over the observation period, whereas the differences in relative effects between cohabiting and not-cohabiting parents became more pronounced. The decline in importance of socio-demographic variables for the choice of family status at the time of first birth may be seen as an indicator that cohabitation has become a more broadly accepted family status. The changes may, however, in part be influenced by changes in welfare policies during the 1990’s.