This paper estimates people’s taste for living with own-ethnic-group neighbors using variation from a natural experiment in Singapore: ethnic housing quotas. I develop a location choice model that informs the use of policy variation from the quotas to address endogeneity issues well-known in the social interactions literature. I assembled a dataset on neighborhood level ethnic proportions by matching more than 500,000 names in the phonebook to ethnicities. I find that all groups want to live with some own-ethnic-group neighbors but they also exhibit inverted U-shaped preferences so that once a neighborhood has enough own-ethnic-neighbors, they would rather add a new neighbor from other groups. Welfare simulations show that about 30% of the neighborhoods are within one standard deviation of the first best allocation of ethnic groups.

Developing countries face massive urbanization and slum upgrading is a popular policy to improve shelter for many. Yet, preserving slums at the expense of formal developments can raise concerns of misallocation of land. We estimate causal, long-term impacts of the 1969–84 KIP programme, which provided basic upgrades to 5 million residents covering 25% of land in Jakarta, Indonesia. We assemble high-resolution data on programme boundaries and 2015 outcomes and address programme selection bias through localized comparisons. On average, KIP areas today have lower land values, shorter buildings, and are more informal, per a photographs-based slum index. The negative effects are concentrated within 5 km of the CBD. We develop a spatial equilibrium model to characterize the welfare implications of KIP. Counterfactuals suggest that 79% of the welfare effects stem from removing KIP in the centre and highlight how to mitigate losses to displaced residents.