Can we attribute economic inequality to our preferences?
Differences in education, skills, occupations, productivity, geography, inherited wealth, labor-market institutions, taxation, and access to economic opportunities are typically considered when discussing economic inequality. However, an underrated idea in explaining this disparity are the individuals’ preferences and their choices themselves, in particular, how they match with their partners. People tend to form partnerships within particular social, educational, occupational, and geographic environments. This means that household income depends on how much individuals earn and also on who ends up with whom.
For example, higher educational attainment is associated with higher expected earnings. If an individual holds an advanced degree, they are more likely to match with someone with a similar educational background. Their earning capacities are concentrated and combined within the same households, and vice versa. The slightest change in this preference pattern, ceteris paribus, might change the distribution of household income.
Economists and sociologists call this positive assortative mating: the tendency for individuals to form partnerships with people who have similar characteristics.
The marriage market structure and individual preferences both come into play. Access to universities, workplaces, neighbourhoods, professional networks, migration, and social circles all form the probability of individuals meeting each other. Greenwood et al. (2014) use several decades of US Census data to demonstrate how spouses match by educational attainment and how assortative mating affects inequality. Then they conducted an experiment where they constructed contingency tables and counterfactual distributions with random pairings, and found that when randomly matched, the Gini coefficients fell by a significant amount in 2005, while only small change was observed compared to data in 1960. The main difference is that by 2005, more women with higher education were able to work and there was higher female labor force participation. Thus, as women were able to contribute to household earnings, the household combined income increased, signaling that positive assortative mating may have had an impact on the Gini coefficients and increasing inequality.
Indonesia as a unique case
Most existing studies focused on the characteristics such as educational attainment, income and wealth, as they are linked to economic resources. Indonesia provides a case for more nuances to the positive assortative mating concept, with the country’s legal and social structures playing a part.
Evidence from Brazil, Indonesia, Mexico, and South Africa suggests that educational sorting within households was present in all four countries, with implications for the distributions of income. Zooming into Indonesia, a separate study used SUSENAS 2022 and the Indonesian Family Life Survey to demonstrate a correlational, not causational, relationship between educational assortative mating and per-capita expenditure inequality in West Java.
In Indonesia, religion plays a relevant part. While Indonesia, the world’s largest Muslim population, officially recognizes six religions, the state only recognizes Muslim marriages registered through KUA, which only recognizes marriages when partners are of the same religion, meaning that religion can shape who is eligible to marry whom.
Ethnicity may provide another dimension of sorting. Previous research using data from 47 million couples from the 2010 Census in Indonesia found that endogamy (the cultural or social practice of marrying strictly within a specific group) tends to be more prevalent among larger ethnic groups, while in Jakarta and North Sumatra, younger, more highly educated, and urban individuals were less likely to marry within their own ethnic group. The study also finds that provincial endogamy rates are negatively associated with indicators of economic development.
For Indonesia, we ask: Does assortative mating matter for the inequality in Indonesia? If so, does the answer differ across regions, between highly urbanised areas, and places where family, religious, and ethnic networks play a larger role in shaping marriage markets?
However, what does this look like in the data?
In our upcoming follow-up piece, we turn to Indonesia and use SUSENAS data to examine patterns of assortative marriage, how these patterns differ across demographic and geographic groups, and the extent to which they may be associated with household economic inequality.
For further reading:
Greenwood, J., Guner, N., Kocharkov, G., & Santos, C. (2014). Marry Your Like: Assortative Mating and Income Inequality. American Economic Review.
Kujundzic, A. (2025). Educational Assortative Mating and Household Income Inequality: Evidence from Brazil, Indonesia, Mexico, and South Africa. arXiv:2503.02713.
Samudra, R., & Wisana, I.D.G.K. (2015). Love Between Us: Educational Assortative Mating and Expenditure Inequality in Indonesia. Universitas Indonesia.
Utomo, A., & McDonald, P. (2016). Who marries whom? Ethnicity and marriage pairing patterns in Indonesia. Asian Population Studies, 12(1), 28–49. https://doi.org/10.1080/17441730.2015.1130327
Menarik sekali melihat perspektif Anip & Lulu dari artapala, dimana pernikahan bukan hanya sebagai keputusan personal, tetapi juga sebagai bagian dari mekanisme sosial dan ekonomi yang memengaruhi distribusi kesejahteraan.
Setelah saya merenung, pertanyaan yang muncul di benak saya yaitu sejauh mana assortative mating benar-benar menjadi salah satu faktor yang memperbesar inequality, dan sejauh mana ia justru merupakan konsekuensi dari inequality yang sudah ada sebelumnya?
Orang dengan pendidikan, pendapatan, lingkungan kerja, tempat tinggal, dan networkinh sosial yang relatif sama memang betul memiliki probabilitas lebih besar untuk bertemu dan akhirnya memilih satu sama lain.
Sehingga dalam perspektif ekonomi dan sosial, ini menimbulkan persoalan endogeneity yang menarik. Apakah preferensi individu membentuk struktur ketimpangan, atau struktur kesempatan yang tidak merata sejak awal yang membentuk preferensi dan pilihan pasangan tersebut?
Pertanyaan berikutnya yang ada di benak saya adalah: jika pola ini di Indonesia memang berkontribusi terhadap intergenerational inequality, apakah persoalan kebijakannya terletak pada siapa menikah dengan siapa, atau lebih pada bagaimana negara memperluas akses pendidikan, mobilitas sosial, pekerjaan, dan interaksi lintas kelompok sehingga marriage market sendiri menjadi lebih terbuka?
Pada akhirnya, ekonomi dan sosiologi membantu kita memahami pola manusia melalui data, probabilitas, dan teori. Tetapi kehidupan manusia tetap memiliki dimensi yang tidak seluruhnya masuk ke dalam model.
Sebagai pengingat pribadi, 2 Korintus 6:14 dan Kejadian 2:18 menekankan kepada kita dalam mencari "Pasangan yang Sepadan" bukan hanya dalam aspek duniawi namun "Sepadan juga dalam Kerohanian"
Kita sebagai manusia boleh membangun teori tentang matching, preference, dan probability. Pada akhirnya, ada bagian dari perjalanan hidup yang tetap berada dalam kehendak dan penetapan Tuhan. God Bless.