Knowledge that Transforms

In January 1995, US President Bill Clinton organized a bailout for Mexico that imposed penalty interest rates and induced the Mexican government to reduce its debt, ending the debt crisis. Can the Troika (European Commission, European Central Bank, and International Monetary Fund) organize similar bailouts for the troubled countries in the eurozone? Our analysis suggests that debt levels are so high that bailouts with penalty interest rates could induce the eurozone governments to default rather than reduce their debt. A resumption of economic growth is one of the few ways that the eurozone crises can end.

Firms' incentives to manufacture biased user reviews impede review usefulness. We examine the differences in reviews for a given hotel between two sites: Expedia.com (only a customer can post a review) and TripAdvisor.com (anyone can post). We argue that the net gains from promotional reviewing are highest for independent hotels with single-unit owners and lowest for branded chain hotels with multiunit owners. We demonstrate that the hotel neighbors of hotels with a high incentive to fake have more negative reviews on TripAdvisor relative to Expedia; hotels with a high incentive to fake have more positive reviews on TripAdvisor relative to Expedia.

Public transit accounts for 1 percent of US passenger miles traveled but attracts strong public support. Using a simple choice model, we predict that transit riders are likely to be individuals who commute along routes with severe roadway delays. These individuals' choices thus have high marginal impacts on congestion. We test this prediction with data from a strike in 2003 by Los Angeles transit workers. Estimating a regression discontinuity design, we find that average highway delay increases 47 percent when transit service ceases. We find that the net benefits of transit systems appear to be much larger than previously believed.

We formally characterize predatory pricing in a modern industry-dynamics framework that endogenizes competitive advantage and industry structure. As an illustrative example we focus on learning-by-doing. To disentangle predatory pricing from mere competition for efficiency on a learning curve we decompose the equilibrium pricing condition. We show that forcing firms to ignore the predatory incentives in setting their prices can have a large impact and that this impact stems from eliminating equilibria with predation-like behavior. Along with the predation-like behavior, however, a fair amount of competition for the market is eliminated.

We develop a model of households with multiple needs (smoothing shocks, financing investment) and constraints (limited credit, self-control issues) in order to examine the nature of household's financing constraints in a developing country, and the impact of relaxing them. We show that increased access to credit has very different implications for the aggregate model economy depending on its form: asset-financed or cash. We then illustrate how a short-term increase in access to loans leads to very distinct behavior in the short run. The relevance of the model can be evaluated using a field experiment, which we are currently implementing in Uganda.

Popular accounts suggest that advertising revenue per unit of consumer attention is lower online than offline, and has fallen in traditional media as the Internet has made advertising markets more competitive. I assess these claims theoretically and empirically, and compare the patterns we observe for the Internet to trends in advertising around the introduction of television and radio. The evidence suggests that the price of attention for similar consumers is actually higher online than offline, and that the growth of new media is not robustly associated with a declining price of attention.

Ambiguous choice problems which involve three or more outcome values can reveal aspects of ambiguity and ambiguity aversion which cannot be displayed in the classic two-outcome Ellsberg urn problems, and hence are not always captured by models designed to accommodate them. These aspects include Allais-type preferences over purely subjective acts, attitudes toward different sources involving different amounts of ambiguity, and attitudes toward ambiguity at different outcome levels. This paper presents a few such examples, and examines the standard models' predictions and performance in such cases.

Competition to become one of several dominant mobile platforms is intense. Platforms compete for developers, who create applications which make the platform valuable for users. Why doesn't one form of platform governance emerge as superior? This essay will stress the reasons for differentiation and proposes a new argument linked to a platform's “hierarchy.” Hierarchical governance features can help at one moment but then get in the way at a later time. These arguments are illustrated by different approaches to platform governance taken by the major mobile platform sponsors of recent years.

Administrative data from a large and diverse community college are used to examine if underrepresented minority students benefit from taking courses with underrepresented minority instructors. To identify racial interactions, we estimate models that include both student and classroom fixed effects and focus on students with limited choice in courses. We find that the performance gap in terms of class dropout rates and grade performance between white and underrepresented minority students falls by 20 to 50 percent when taught by an underrepresented minority instructor. We also find these interactions affect longer-term outcomes such as subsequent course selection, retention, and degree completion.

An increasingly influential 'technological-discontinuity' paradigm suggests that IT-induced technological changes are rapidly raising productivity while making workers redundant. This paper explores the evidence for this view among the IT-using US manufacturing industries. There is some limited support for more rapid productivity growth in IT-intensive industries depending on the exact measures, though not since the late 1990s. Most challenging to this paradigm, and to our expectations, is that output contracts in IT-intensive industries relative to the rest of manufacturing. Productivity increases, when detectable, result from the even faster declines in employment.