Jaemin Woo

More than four in five partisan couples in the United States today share party identity. Nearly half of adults aged 25-45 are unpartnered. We estimate how much of this sorting and singlehood reflects partisan aversion in partner choice. Observed matches confound preferences with availability. To separate them, we run a discrete choice experiment on approximately 1,000 Democrats and Republicans aged 25-45 in which party identity, education, and income vary independently across partner profiles. Randomization identifies willingness to pay for partisan alignment, independent of local market composition. Democratic types would give up about $210,000 and Republican types about $100,000 in annual partner income to avoid a typical cross-party partner. We embed these preferences in a transferable-utility matching model calibrated to observed population shares and couple-type distributions. Removing partisan aversion while holding composition fixed substantially reduces singlehood and sharply increases the cross-party couple share, with economically meaningful welfare gains in partner-income equivalents. Equalizing partisan composition while holding preferences fixed has much smaller effects, since a modest gender gap in party shares cannot offset large preference penalties on cross-party matches. Republican types gain most from removing aversion, especially college-educated Republicans, because they are the smaller group and gain access to the much larger Democratic pool, while the larger Democratic types gain least.

We study fertility in a dynamic spatial equilibrium model with endogenous location and residential choices, alongside investments in children's education. We estimate the model using near-universal administrative microdata from South Korea, drawing on census records, credit bureau data linked to mobile phone mobility records, and government administrative sources. Our estimates indicate that high commuting and housing costs, combined with intensive education investments in large cities, where the amenity of living is large, substantially reduce fertility. We conduct a decomposition exercise to explain the sharp decline in South Korean fertility over the past decade, finding that deteriorating child-rearing amenities and rising education costs play a significant role. Finally, we conduct a series of counterfactual exercises considering place-based policies to reduce commuting costs, increase housing supply, or lower education costs. We find that policies focusing exclusively on large cities, such as Seoul, may have the opposite effect on fertility than intended due to spatial sorting. However, a combination of nationwide policies targeting the fertility margin directly can boost fertility significantly.