How the New Model of Marriage May Drive Income Inequality

(Photo: Boston Public Library)

Our last two podcasts, “Why Marry?” (Part 1 and Part 2) explored the broad and deep changes in the institution of marriage. One theme was that the old marriage model of “production complementaries” has shifted to one based on “consumption complementarities.” Here’s Justin Wolfers on the subject:

We have more time, more money, and so you want to spend it with someone that you’ll enjoy. So, similar interests and passions. We call this the model of hedonic marriage. But really it’s a lot more familiar than that. This is just economists giving a jargon name to love. So you want someone who’s actually remarkably similar to you or has similar passions that you do. So it fundamentally changes who marries who.

But is this change also related to income inequality? Wolfers briefly referenced that idea a few years back; in a recent article for Vox, the economics Jeremy Greenwood, Nezih Guner, Georgi Kocharkov, and Cezar Santos further the argument:

Think about the following simple thought experiment. Suppose that there are only two types of people, equal in numbers, those that went to college and those who did not. Those who went to school earn $30 and those who did not earn $10. If educated men marry uneducated women and uneducated men marry educated women, then every household will earn $40 in total. So, household income is perfectly equalised. Now, imagine a world in which educated people only marry other educated people. Then, a household made up of an educated man and an educated woman will earn $60 versus the $20 earned by a household that consists of only uneducated spouses. The households at the top of the distribution would have three times the income of those at the bottom.

Obviously, the example above is a dramatic simplification of reality, but it does capture an important trend that is actually taking place in the U.S. economy. To study its impact, we track samples of hundreds of thousands of households from the U.S. Census Bureau for the period 1960 to 2005 (see Greenwood, Guner, Kocharkov and Santos 2014). The upshot of the analysis is that rising assortative mating together with increasing labour-force participation by married women are important in order to account for the determinants of growth in household income inequality in the U.S.