We present and estimate a model with strategic complementarities in firms' choices of on-time or delayed wage payment. Linked employer-employee panel data from Russia facilitate identification of the endogenous interactions through fixed effects for firms, workers, and local labor markets, and instrumental variables based on policy interventions. The estimated reaction function displays strongly positive neighborhood effects, and the estimated feedback loops—worker quits, effort, strikes, and legal penalties—imply that costs of wage delays are attenuated by neighborhood arrears. We also study a nonlinear case with two stable symmetric equilibria: a punctual payment and a late payment equilibrium.

This paper identifies a new factor, the age of the housing stock, that affects where high- and low-income neighborhoods are located in U.S. cities. High-income households, driven by a high demand for housing services, tend to locate in areas of the city where the housing stock is relatively young. Because cities develop and redevelop from the center outward over time, the location of these neighborhoods varies over the city's history. The model predicts a suburban location for the rich in an initial period, when young dwellings are found only in the suburbs, while predicting eventual gentrification once central redevelopment creates a young downtown housing stock. Controlling for other determinants of where the poor live (e.g., proximity to amenities and public transit), empirical work indicates that if the influence of spatial variation in dwelling ages were eliminated, central-city/suburban disparities in neighborhood economic status would be reduced by up to 10 percentage points. Model estimates further predict that between 2000 and 2020, central-city/suburban differences in economic status will narrow in cities of all sizes, and especially in the larger metropolitan areas as American cities become more gentrified.

We examine the impact of recent state-level Medicaid policy changes that expanded eligibility for family planning services to higher-income women and to Medicaid clients whose benefits would expire otherwise. We show that the income-based policy change reduced overall births to non-teens by about 2% and to teens by over 4%; estimates suggest a decline of 9% among newly eligible women. The reduction in fertility appears to have been accomplished via greater use of contraception. Our calculations indicate that allowing higher-income women to receive federally funded family planning cost on the order of $6,800 for each averted birth.