Internal migration, group size, and ethnic endogamy in Indonesia

Abstract

Much of the literature on assortative mating has centred on the social contexts of immigrant-receiving countries in the West. This article examines ethnic assortative mating (endogamy) against rising volumes and intensity of migration within a multi-ethnic lower middle-income country. We used full enumeration data from the 2010 Indonesian Population Census to create a national dataset of husband–wife pairs (n = 47.8 million couples), and five subsets of married couples from provinces with the highest proportion of lifetime migrants: Riau, Riau Islands, Jakarta, East Kalimantan, and West Papua (n = 4.05 million). First, we examined the association between migration, group size, and endogamy at the provincial level. We found a negative association between internal migrant stock and endogamy across 33 provinces in Indonesia. Using endogamy as a proxy of the strength of ethnic boundaries, we have shown that accounting for group size at the provincial level changes the overall ranking of endogamy among ethnic groups. Second, drawing on the subsets of couples in the five provinces with the highest proportion of migrants in their population, we used multivariate analysis to examine how migration status correlates with the likelihood of endogamy at the individual level. Controlling for sex, group size, age, education, and religion, we found that the relationship between an individual's migration status and endogamy varies across the five provinces, reflecting the different nature and history of migration, and the ethno-religious composition in these regions.