Two-sex models – Time for a rethink?

Michael Murphy, London School of Economics and Political Science (LSE)

Two-sex models have been a long-standing topic of interest in demography. However, in contemporary populations, increasing numbers of marriages occur between partners of different nationalities, which makes the usual assumption of a well-defined pool of eligibles in a ‘marriage market’ increasingly difficult to justify. Contemporary patterns are better-characterized as a series of pools of potential partners, with an individual being more likely to find a partner from those who are ‘local’, where ‘local’ may include social as well as geographical space. I consider how to recover the structure of such local markets from analysis of the numbers of marriage taking pace with a partner in different groups (in this case 1.1 million marriages that took place in the 433 municipalities in Norway in the period 1974-2003). I discuss the construction of metrics for the closeness of two areas according to the number of marriages that occur between members of these areas. The issue of allowing for different sizes of areas and the possible effect of competing areas is considered. A number of non-linear metrics are considered and the feasibility of applying them to matrices of sizes of magnitude of 400 by 400 is assessed. No unique solution is found to the definition for such local marriage markets, but a series of approaches that permit identification of such clusters of areas are identified.