Socio-economic homogamy and its effects on the stability of cohabiting unions
Authors: Mäenpää Elina 
Published: June 2020

The tendency towards socio-economic homogamy – partner similarity in terms of socio-economic status – is of great interest to social scientists, for two reasons. First, socio-economic homogamy is an indicator of social closure between status groups in a society. Second, given that homogamy leads to the accumulation of advantageous and disadvantageous socio-economic conditions within couples, it also intensifies social and economic inequalities between families. The objective of this thesis is to enhance knowledge of socio-economic homogamy and its consequences for union stability in Finland. The first aim was to analyse the strength and patterns of socio-economic homogamy in partner choice. The second aim was to determine whether and, if so, how homogamy is associated with the likelihood of ending non-marital cohabitation – through separation on the one hand, or marriage on the other. In addition, two dimensions of socio-economic status, individual educational attainment and social class of the family of origin, were analysed to find out whether matching on individually achieved status or on the status of the parental family had a bigger effect on union dynamics.The analyses were based on sets of register data compiled at Statistics Finland. Log-linear models were applied to study homogamy tendencies and their changes in marriages and cohabitations of women born in 1957–1979 at the age of 30. The effects of homogamy and heterogamy on the likelihood of separation and marriage were analysed with Cox proportional hazards model in cohabitations formed in the period 1995–2002 by women born in 1960–1977. An elaborate approach was adopted: marriage and separation rates were examined in each possible combination of partner status.The results imply that people tend to choose partners who are similar to them in terms of educational attainment and class background. However, homogamy was stronger with regard to education than to social-class origins. This is line with the view that boundaries based on achieved status are more difficult to cross in modern, individualized societies than boundaries based on social origins. The most highly educated – those with a higher university degree – were particularly strongly inclined towards homogamy. The general strength of homogamy did not change much across the birth cohorts from the late 1950s to the 1970s, but the trends differed depending on the level of education: homogamy strengthened among those with a low level of education, and weakened among the highly educated. The results also indicate that in the absence of homogamy, women increasingly tend to have partners whose level of education is lower than theirs.Homogamy in class background had a relatively weak influence on the stability of cohabiting unions. Homogamy increased the marriage rate among the children of farmers, whereas heterogamy was associated with an increased separation risk when one partner came from a farmer family and the other from an upper-white-collar family. Educational differences played a somewhat more significant role in these transitions. Homogamy was associated with a reduced risk of separation among the most highly educated cohabitors in particular. The effects of educational homogamy on the marriage rate were less consistent: homogamy increased the marriage rate among cohabitors with a basic-level education, but reduced it among the most highly educated.The findings reveal that status barriers and cultural differences are of significance in partner choice and the stability of cohabiting unions in Finland, and that group boundaries based on achieved status are stronger than those based on ascribed status in terms of union dynamics.