Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...

We apply the method of constrained asset share estimation (CASE) to test the mean-variance efficiency (MVE) of the stock market. This method allows conditional expected returns to vary in relatively unrestricted ways. The data estimate reasonably the price of risk, and, in some cases, the MVE...

We construct factors from a cross section of exchange rates and use the idiosyncratic deviations from the factors to forecast. In a stylized data generating process, we show that such forecasts can be effective even if there is essentially no serial correlation in the univariate exchange rate...

We investigate the link between real exchange rates and sectoral total factor productivity measures for countries in the Eurozone. Real exchange rate patterns closely accord with an amended Balassa-Samuelson interpretation, both in cross-section and time series. We construct a sticky price...

Failures of the law of one price explain much of the variation in real C.P.I. exchange rates. We use C.P.I. data for U.S. cities and Canadian cities for 14 categories of consumer prices to examine the nature of the deviations from the law of one price. The distance between cities explains a...

Using a sample of Harvard undergraduates, we analyze trust and social capital in two experiments. Trusting behavior and trustworthiness rise with social connection; differences in race and nationality reduce the level of trustworthiness. Certain individuals appear to be persistently more...