Mismatch: A novel explanation for the decline in co-residential partnerships in the Nordic countries

Couple co-residence is declining in Finland and Sweden. In particular, increasingly, less well-off individuals are not sharing a household with their romantic partners. Why is this so?

Previous research has focused increase in individualism and living costs, but evidence is not congruent with such frameworks.

Drawing on insights from demography and history, this project proposes that changes in sex-ratios within groups who traditionally form unions together, particularly socioeconomic groups and ethnic groups, impact on the share never-partnered in the population.Using unique administrative registers from Sweden and Finland, this is the first project to develop and comprehensively analyse this explanation.

Data allows a population-wide measure of cohabitation rather than marriage only, thereby surpassing a longstanding bottleneck in the literature.Household structures are decisive for material depravation, child poverty and fertility.

Moreover, households are basic organizing structures of everyday life and grasping why they change are fundamental to understanding contemporary society.

Therefore, an accurate understanding of the driving forces behind change in partner co-residence is a fundamental scientific task, that also provides a firm ground for policy development.The findings will improve understanding of why fewer people are co-residing and the increased socioeconomic disparities in couple co-residence, and to advance theoretical developments on this topic.