Knowledge that Transforms

We measure price-level uncertainty and instability in the United States over the period 1850 to 2012. Major outbreaks of price-level uncertainty and instability occur both before and after World War II, alternating with three price-level moderations: one near the turn of the twentieth century, another under Bretton Woods, and a third in the 1990s. There is no evidence that the price level was systematically more stable or less uncertain before or after World War II. Moderations sometimes involved links to gold, but the experience of the 1990s proves that a well-managed fiat regime can achieve the same outcome.

Regulations aimed at curbing the entry of large retail stores have been introduced in many countries to protect independent retailers. Analyzing a planning reform launched in the United Kingdom in the 1990s, I show that independent retailers were actually harmed by the creation of entry barriers against large stores. Instead of simply reducing the number of new large stores entering a market, the entry barriers created the incentive for large retail chains to invest in smaller and more centrally located formats, which competed more directly with independents and accelerated their decline. Overall, these findings suggest that restricting the entry of large stores does not necessarily lead to a world with fewer stores, but one with different stores, with uncertain competitive effects on independent retailers.

We investigate the success of legislation aimed at increasing competition at highly concentrated U.S. airports, mainly by forcing these airports to increase the availability of scarce facilities. We use a multidimensional regression-discontinuity approach to exploit a sharp discontinuity in the law’s implementation and identify its effects. We find that fares decrease by 13.4% (20.2%) in markets with one (both) end point(s) covered. Approximately half of the decline is driven by the entry of low-cost carriers. We find little evidence that the fare declines were accompanied by a diminished quality of service, and passenger volumes increased, which suggests the legislation improved consumer welfare.

Regression and SDF approaches with centered or uncentered moments and symmetric or asymmetric normalizations are commonly used to empirically evaluate linear factor pricing models. We show that unlike two-step or iterated GMM procedures, single-step estimators such as continuously updated GMM yield numerically identical risk prices, pricing errors, and overidentifying restrictions tests irrespective of the model validity and regardless of the factors being traded, or the use of excess or gross returns. We illustrate our results with Lustig and Verdelhan’s (2007) currency returns, propose tests to detect some problematic cases, and provide Monte Carlo evidence on the reliability of asymptotic approximations.

We examine variety pass-through effects that occur when multiproduct retailers adjust the length of their product lines in response to changes in wholesale prices. Studying variety pass-through is essential to understanding how wholesale price changes transmit into retail prices when variety is endogenous. Using data from the ready-to-eat breakfast cereal category, we find that retailers jointly adjust retail prices and the length of their product lines in response to changes in wholesale prices. We show the importance of controlling for the endogeneity of retailers’ product line decisions when calculating price pass-through rates.

Empirical researchers interested in the causal effect of the endogenous regressor often use instrumental variables. When few valid instruments are available, they typically estimate restricted specifications that impose uniform per unit treatment effects, even when these effects are likely to vary. We show that in these cases, ordinary least squares and instrumental variables estimators identify different weighted averages of all per unit effects, so the traditional Hausman test is uninformative about endogeneity. We develop a new exogeneity test that works even when the true model cannot be estimated using IV methods as long as a single valid instrument is available. We revisit three recent empirical examples to demonstrate the practical value of our test.

We link data on racial self-identification with changes in state-level affirmative action policies to ask whether racial self-identification responds to economic incentives. We find that after a state bans affirmative action, multiracial individuals who face an incentive to identify under affirmative action are about 30 percent less likely to identify with their minority groups. In contrast, multiracial individuals who face a disincentive to identify under affirmative action are roughly 20 percent more likely to identify with their minority groups once affirmative action policies are banned.

This research examines the climatic origins of the diffusion of Neolithic agriculture across countries and archaeological sites. The theory suggests that a foraging society's history of climatic shocks shaped the timing of its adoption of farming. Specifically, as long as climatic disturbances did not lead to a collapse of the underlying resource base, the rate at which hunter-gatherers were climatically propelled to experiment with their habitats determined the accumulation of tacit knowledge complementary to farming. Consistent with the proposed hypothesis, the empirical investigation demonstrates that, conditional on biogeographic endowments, climatic volatility has a hump-shaped effect on the timing of the adoption of agriculture.

A common assumption is that the rise of drug testing among U.S. employers must have had negative consequences for black employment. I use variation in the timing and nature of drug testing regulation to identify the impacts of testing on black hiring. I find that adoption of protesting legislation increases black employment in the testing sector by 7% to 30% and relative wages by 1.4% to 13.0%, with the largest shifts among low-skilled black men. The results are consistent with ex ante discrimination and suggest that drug testing may benefit African Americans by enabling nonusing blacks to prove their status to employers.

Some have suggested that housing policy, embodied by the Community Reinvestment Act (CRA) and affordable housing goals of the government-sponsored enterprises (GSEs), caused the subprime crisis. We examine if these programs led to worse mortgage outcomes using two approaches. The first examines whether more activity by CRA-covered lenders, or more loan sales to the GSEs, was associated with worse outcomes. The second uses regression discontinuity to determine if outcomes were worse at the geographic thresholds used by each program. Our results suggest that neither program played a significant role in the subprime crisis.