MARRIAGE MARKETS: birth cohorts, age gaps and the position of women

The global increase in birth rates over the past decades, coupled with the tendency of men to marry younger women, has led to imbalances in the so-called “marriage market” which have in turn prompted an increase in practices such as polygyny and dowry-payments in South Asia and sub-Saharan Africa.

These are the core findings of new research published in the November 2019 issue of The Economic Journal, which looks at how demographic trends and changes in birth cohorts have affected the position of women across the world.

The status of women has progressed considerably over the past century, but there are still some puzzling steps backward. In India, for example, the practice of dowry payments has increased and even spread to parts of the country where it was earlier unknown. Similarly in Africa, polygyny persists and is socially acceptable despite modernisation.

The authors of this paper ask why the forward march of women has been interrupted in these developing countries and whether this trend is likely to persist, studying demographic trends to explain the shift, with a focus on the age between men and their wives.

Men usually marry younger women – this is true in every country for which data is available, with an average gap ranging from two to seven years. For most of human history this age gap has not mattered, since human populations have been stationary. However, as countries develop, birth cohorts start growing in size, at 2 percent or 3 percent a year. If the age gap at marriage is five years, the cohort of men born in a given year will be matched with the cohort of women born five years later and the latter cohort will be 10–15 percent larger (if the sex ratio within each cohort is balanced).

This implies a very large excess of women on the marriage market, and one can expect adverse consequences for them, at marriage and later within the household, since their bargaining position is considerably reduced. In many sub-Saharan African countries such as Senegal, birth cohorts are increasing at 2 percent per year, and this growth shows no signs of tapering off. Since these countries have a large gap at marriage, this magnifies the imbalance and provides ample opportunities for many men to indulge in polygyny.

The question arises, will the age gap adjust downward, in order to reduce these imbalances. Although the simple intuition of supply and demand suggests so, my paper shows that this will not be the case. In particular, even though the age-gap adjusts to reduce imbalances when there are shocks to cohort size or the sex ratio, it will not adjust when there are secular or long-run imbalances.

However, these demographic trends have now been reversed in many countries. As women have become more educated and fertility has declined, cohorts have now started shrinking. This effect is most pronounced in East Asia, with cohort sizes in South Korea declining at 2–4 percent per year.

Each cohort of men is now matched with a smaller cohort of women, giving rise to a shortage of women. In China, this imbalance is aggravated by the male-biased sex-ratio a birth. One should expect to see a significant improvement in the position of women, as their bargaining position improves.

Trends in East Asia are portents for the rest of the developing world. Cohort-size growth has
now declined in other Asian countries and is turning negative. This is also true in the countries of the Arab Spring, such as Tunisia. The reversal of trend has major social consequences. As fertility declines further, and cohort sizes fall, a woman will not only have better options, but these will also  improve her bargaining position and her say within marriage.

The Demographic Transition and the Position of Women: A Marriage Market Perspective is published by V. Bhaskar is published in the November 2019 issue of The Economic Journal

V. Bhaskar

Professor of Economics at University of Texas at Austin