Intermarriage: Opportunity and Preference

The two-sex problem in the analysis of nuptiality can be reduced to the problem of separating factors that determine the opportunity to choose a certain category of marriage partner from factors representing preference for the same type of partner. A theory that enables opportunity factors to be separated from preference factors is presented in this paper, in the context of analysing the phenomenon of intermarriage. An index called ‘the marital index of social distance’ is derived and its properties discussed. The index, representing preference factors free of opportunity factors, can be calculated easily from marriage statistics detailing group affiliations of brides and grooms. The theory is applied to data on in-marriage of Australian sub-populations defined by birthplace, for the period 1954–83. It is shown that marital indices of social distance have remained relatively constant over time compared with in-marriage rates which have fluctuated according to representation in the marriage market.