HIER 2003 Abstracts

1992. Marcelo J. Moreira
A General Theory of Hypothesis Testing in the Simul­taneous Equations Model
Abstract | Paper
Classical exponential-family statistical theory is employed to characterize the class of exactly similar tests for a structural coefficient in a simultaneous equations model with normal errors and known reduced-form covariance matrix. We also find a necessary condition for tests to be unbiased and derive their power envelope. When the model is just-identified, we show that the Anderson-Rubin score, and conditioal likelihood ratio tests are optimal. When the model is over-identified, there exists no optimal tests. Nevertheless, Monte Carlo simulations indicate that the power curve of the conditional likelihood ratio tests is reasonably close to the power envelope.

1993. Marcelo J. Moreira and Brian P. Poi
Implementing Tests with Correct Size in the Simultaneous Equation Model
Abstract | Paper
This paper fixes size distortions of tests for structural parameters in the simultaneous equations model by computing critical value functions based on the conditional distribution of test statistics. The conditional tests can then be used to construct informative confidence regions for the structural parameter with correct coverage probability. Commands to implelment these tests in Stata are also introduced.

1994. David M. Cutler, Edward L. Glaeser, and Jesse M. Shapiro
Why Have Americans Become More Obese?
Abstract | Paper
Americans have become considerably more obese over the past 25 years. This increase is primarily the result of consuming more calories. The increase in food consumption is itself the result of technological innovations which made it possible for food to be mass prepared far from the point of consumption, and consumed with lower time costs of preparation and cleaning. Price changes are normally beneficial, but may not be if people have self-control problems. This applies to some, but not most, of the population.

1995. Alberto Alesina, Enrico Spolaore, and Romain Wacziarg
Trade, Growth, and the Size of Countries
Abstract | Paper
Normally, economists take the size of countries as an exogenous variable which does need to be explained. Nevertheless, the borders of countries and therefore their size change, partially in response to economic factors such as the pattern of international trade. Conversely, the size of countries influences their economic performance and their preferences for international economic policies - for instance smaller countries have a greater stake in maintaining free trade. In this paper we review the theory and the evidence concerning a growing body of research that has considered both the impact of market size on growth and the endogenous determination of country size. We show that our understanding of economic performance and of the history of international economic integration can be greatly improved by bringing the issue of country size at the forefront of the analysis of growth.

1996. Michael Ostrovsky and Michael Schwarz
Equilibrium Information Disclosure: Grade Inflation and Unraveling
Abstract | Paper
This paper explores information disclosure in matching markets, e.g. the informativeness of transcripts given out by universities. We show that the same amount of information is disclosed in all equilibria. We then demonstrate that if universities disclose the equilibrium amount of information, students and employers will not find it profitable to contract early; if they disclose more, unraveling will occur.

1997. Laurence Ball, N. Gregory Mankiw and Ricardo Reis
Monetary Policy for Inattentive Economies
Abstract | Paper
This paper is a contribution to the analysis of optimal monetary policy. It begins with a critical assessment of the existing literature, arguing that most work is based on implausible models of inflation-output dynamics. It then suggests that this problem may be solved with some recent behavioral models, which assume that price setters are slow to incorporate macroeconomic information into the prices they set. A specific such model is developed and used to derive optimal policy. In response to shocks to productivity and aggregate demand, optimal policy is price level targeting. Base drift in the price level, which is implicit in the inflation targeting regimes currently used in many central banks, is not desirable in this model. When shocks to desired markups are added, optimal policy is flexible targeting of the price level. That is, the central bank should allow the price level to deviate from its target for a while in response to these supply shocks, but it should eventually return the price level to its target path. Optimal policy can also be described as an elastic price standard: the central bank allows the price level to deviate from its target when output is expected to deviate from its natural rate.

1998. Elhanan Helpman, Marc J. Melitz and Stephen R. Yeaple
Export versus FDI
Abstract | Paper
This paper builds a multi-country, multi-sector general equilibrium model that explains the decision of heterogeneous firms to serve foreign markets either through exports or local subsidiary sales (FDI). These modes of market access involve different relative costs, some of which are sunk while others vary with sales volume (such as transport costs and tariffs). Relative to investment in a subsidiary, exporting involves lower sunk costs but higher per-unit costs. In equilibrium, only the more productive firms choose to serve the foreign markets and the most productive among this group will further choose to serve the overseas market via FDI. The paper then explores several implications of the individual firms' decisions for aggregate export and FDI sales relative to the domestic and foreign market sizes. In particular, it is shown that firm level heterogeneity is an important determinant of relative export and FDI flows.

We use the model to derive testable empirical predictions on the relative aggregate export and FDI sales in a given country for a given sector based both on relative costs and the extent of firm level heterogeneity in that sector. These predictions are tested on data of US affiliate sales and US exports in 38 different countries and 52 sectors. The comparative statics based on relative costs are very similar to those tested by Brainard (AER 1997) and are confirmed in our data: sector/country specific transport costs and tariffs have a strong negative effect on export sales relative to FDI. More importantly, our new predictions for the effects of firm-level heterogeneity on the relative export and FDI sales are also strongly supported by the data: more heterogeneity leads to significantly more FDI sales relative to export sales.

1999. Laurent Calvet and Adlai Fisher
Regime-Switching and the Estimation of Multifractal Processes
Abstract | Paper
We propose a discrete-time stochastic volatility model in which regimeswitching serves three purposes. First, changes in regimes capture low frequency variations, which is their traditional role. Second, they specify intermediate frequency dynamics that are usually assigned to smooth autoregressive processes. Finally, high frequency switches generate substantial outliers. Thus, a single mechanism captures three important features of the data that are typically addressed as distinct phenomena in the literature. Maximum likelihood estimation is developed and shown to perform well in finite sample. We estimate on exchange rate data a version of the process with four parameters and more than a thousand states. The estimated model compares favorably to earlier specifications both in- and out-of-sample. Multifractal forecasts slightly improve on GARCH(1,1) at daily and weekly intervals, and provide considerable gains in accuracy at horizons of 10 to 50 days.

2000. Andrei Shleifer
Will The Sovereign Debt Market Survive?
Abstract | Paper
Economic theory and evidence from a variety of debt markets shed light on current reform proposals concerning emerging market debt. Debt markets, including the U.S. municipal bond market, generally function best when the rights of creditors are protected most effectively. Since current IMF reform proposals significantly emasculate creditor rights, they are likely to have an adverse effect on the flow of new funds to sovereign borrowers.

2001. Alberto Alesina, Ignazio Angeloni and Federico Etro
International Unions
Abstract | Paper
We model an international union as a group of countries deciding together on the provision of public goods or policies that generate spillovers across members. The trade-off between benefits of coordination and loss of independent policymaking endogenously determines size, composition and scope of the union. Policy uniformity reduces the union’s size, may block enlargement processes and induce excessive centralization. We study flexible rules with non-uniform policies that reduce these ine?- ciencies focusing on arrangements relevant in the context of existing unions or federal states, like enhanced cooperation, subsidiarity, federal mandates and earmarked grants.

2002. Simeon Djankov, Edward L. Glaeser, Rafael La Porta, Florencio Lopez-de-Silanes and Andrei Shleifer
The New Comparative Economics
Abstract | Paper
In recent years, comparative economics experienced a revival, with a new focus on comparing capitalist economies. The theme of the new research is that institutions exert a profound influence on economic development. We argue that, to understand capitalist institutions, one needs to understand the basic tradeoff between the costs of disorder and those of dictatorship. We then apply this logic to study the structure of efficient institutions, the consequences of colonial transplantation, and the politics of institutional choice.

2003. Samuel P. Thompson
Optimal Versus Robust Inference in Nearly Integrated Non Gaussian Models
Abstract | Paper
Abstract: Elliott, Rothenberg and Stock (1996) derived a class of point-optimal unit root tests in a time series model with Gaussian errors. Other authors have proposed “robust” tests which are not optimal for any model but perform well when the error distribution has thick tails. I derive a class of point-optimal tests for models with non Gaussian errors. When the true error distribution is known and has thick tails, the point-optimal tests are generally more powerful than Elliott et al.’s (1996) tests as well as the robust tests. However, when the true error distribution is unknown and asymmetric, the point-optimal tests can behave very badly. Thus there is a tradeoff between robustness to unknown error distributions and optimality with respect to the trend coefficients

2004. Edward L. Glaeser and Matthew E. Kahn
Sprawl and Urban Growth
Abstract | Paper
Cities can be thought of as the absence of physical space between people and firms. As such, they exist to eliminate transportation costs for goods, people and ideas and transportation technologies dictate urban form. In the 21st century, the dominant form of city living is based on the automobile and this form is sometimes called sprawl. In this essay, we document that sprawl is ubiquitous and that it is continuing to expand. Using a variety of evidence, we argue that sprawl is not the result of explicit government policies or bad urban planning, but rather the inexorable product of car-based living. Sprawl has been associated with significant improvements in quality of living, and the environmental impacts of sprawl have been offset by technological change. Finally, we suggest that the primary social problem associated with sprawl is the fact that some people are left behind because they do not earn enough to afford the cars that this form of living requires.

2005. Pol Antras and Elhanan Helpman
Global Sourcing
Abstract | Paper
We present a North—South model of international trade in which differentiated products are developed in the North. Sectors are populated by final-good producers who differ in productivity levels. Based on productivity and sectoral characteristics, firms decide whether to integrate into the production of intermediate inputs or outsource them. In either case they have to decide from which country to source the inputs. Final-good producers and their suppliers must make relationship-specific investments, both in an integrated firm and in an arm’s-length relationship. We describe an equilibrium in which firms with diferent productivity levels choose diferent ownership structures and supplier locations, i.e., they choose different organizational forms. We then study the efects of within-sectoral heterogeneity and variations in industry characteristics on the relative prevalence of these organizational forms. The analysis sheds light on the structure of foreign trade within and across industries.

2006. Harrison Hong, Jeffrey D. Kubik and Jeremy C. Stein
Thy Neighbor's Portfolio: Word-of-Mouth Effects in the Holdings and Trades of Money Managers
Abstract | Paper
A mutual-fund manager is more likely to hold (or buy, or sell) a particular stock in any quarter if other managers in the same city are holding (or buying, or selling) that same stock. This pattern shows up even when controlling for the distance between the fund manager and the stock in question, so it is distinct from a local-preference effect. It is also robust to a variety of controls for investment styles. These results can be interpreted in terms of an epidemic model in which investors spread information about stocks to one another by word of mouth.

2007. Harrison Hong and Jeremy C. Stein
Simple Forecasts and Paradigm Shifts
Abstract | Paper
We postulate that agents make forecasts using overly simplified models of the world—i.e., models that only embody a subset of available information. We then go on to study the implications of learning in this environment. Our key premise is that learning is based on a model-selection criterion. Thus if a particular simple model does a poor job of forecasting over a period of time, it is eventually discarded in favor of an alternative, yet equally simple model that would have done better over the same period. This theory makes several distinctive predictions, which, for concreteness, we develop in a stock-market setting. For example, starting with symmetric and homoskedastic fundamentals, the theory yields forecastable variation in the size of the value/glamour differential, in volatility, and in the skewness of returns. Some of these features mirror familiar accounts of stock-price bubbles.

2008. Alberto Alesina and Alexander Wagner
Choosing (And Reneging On) Exchange Rate Regimes
Abstract | Paper
We use data on announced and actual exchange rate arrangements to ask which countries follow de facto regimes different from their de iure ones, that is, do not do what they say. Our results suggest that countries with poor institutional quality have difficulty in maintaining pegging and abandon it more often. In contrast, countries with relatively good institutions display fear of floating, i.e. they manage more than announced, perhaps to signal their differences from those countries incapable of maintaining promises of monetary stability.

2009. Alberto Alesina and Guido Tabellini
Bureaucrats or Politicians?
Abstract | Paper
Policies are typically chosen by politicians and bureaucrats. This paper investigates the criteria that should lead a society to allocate policy tasks to elected policymakers (politicians) or non elected bureaucrats. Politicians tend to be preferable for tasks that have the following features: they do not involve too much specific technical ability relative to effort; there is uncertainty ex ante about ex post preferences of the public and flexibility is valuable; time inconsistency is not an issue; small but powerful vested interests do not have large stakes in the policy outcome; effective decisions over policies require taking into account policy complementarities and compensating the losers; the policies imply redistributive conflicts among large groups of voters. The reverse apply to the attribution of prerogatives to bureaucrats.

2010. Christopher Blattman, Michael A. Clemens and Jeffrey G. Williamson
Who Protected and Why? Tariffs the World Around 1870-1938
Abstract | Paper
This paper uses a new database to establish a set of tariff facts that have not been well appreciated: tariff rates in Latin America were far higher than anywhere else in the century before the Great Depression; while lower than Latin America, tariffs were far higher in the European periphery and the Englishspeaking new world than they were in the European core; tariff rates rose everywhere in the periphery up to 1900, and then moderated a bit up to WWI; and the great anti-global leap during the 1930s in Latin American and the European periphery was not new policy territory since these two regions had plenty of previous experience with very high tariffs. These world tariff facts need an explanation, especially since economic historians have pretty much ignored them while devoting so much attention to Europe. As we search for the explanations, we find that modern endogenous tariff theory isn’t quite up to the task. The paper uses this world wide sample of 35 countries as a panel to explore competing hypotheses as to what drove policy in the century before WWII: revenue motivation; optimal tariffs; strategic tariffs; deindustrialization fears; Stolper-Samueson forces; and many more. The world environment mattered. Trading partners mattered. Domestic geography, factor endowments, institutions and politics mattered.

2011. N. Gregory Mankiw, Ricardo Reis and Justin Wolfers
Disagreement about Inflation Expectations
Abstract | Paper
Analyzing 50 years of inflation expectations data from several sources, we document substantial disagreement among both consumers and professional economists about expected future inflation. Moreover, this disagreement shows substantial variation through time, moving with inflation, the absolute value of the change in inflation, and relative price variability. We argue that a satisfactory model of economic dynamics must speak to these important business cycle moments. Noting that most macroeconomic models do not endogenously generate disagreement, we show that a simple “sticky-information” model broadly matches many of these facts. Moreover, the sticky-information model is consistent with other observed departures of inflation expectations from full rationality, including autocorrelated forecast errors and insufficient sensitivity to recent macroeconomic news.

2012. Ximena Clark, Timothy J. Hatton and Jeffrey G. Williamson
What Explains Cross-Border Migration in Latin America?
Abstract | Paper
What accounts for the differences in rates of emigration from Latin America compared with those from other sending regions such as Asia and Africa? Why do cross-border migration rates vary so much across Latin America? What explains those rates? This paper looks at evidence covering the period between the early 1970s and the late 1990s. It represents the start of a project seeking answers to these questions.

2013. Michael Ostrovsky and Michael Schwarz
Adoption of Standards under Uncertainty
Abstract | Paper
The presence of noise in compliance times may have a critical impact on the selection of new technological standards. A technically superior standard is not necessarily viable because an arbitrarily small amount of noise may render coordination on that standard impossible. The criterion for the viability of a standard is that the sum of \support ratios" of all players must be smaller than one, where \support ratio" is de ned as the ratio of the rm's per-period cost of supporting the standard to the per-period gross bene t that the rm receives after all players comply with the standard.

2014. Edward L. Glaeser and Janet E. Kohlhase
Cities, Regions and the Decline of Transport Costs
Abstract | Paper
The theoretical framework of urban and regional economics is built on transportation costs for manufactured goods. But over the twentieth century, the costs of moving these goods have declined by over 90% in real terms, and there is little reason to doubt that this decline will continue. Moreover, technological change has eliminated the importance of fixed infrastructure transport (rail and water) that played a critical role in creating natural urban centres. In this article, we document this decline and explore several simple implications of a world where it is essentially free to move goods, but expensive to move people. We find empirical support for these implications.

2015. Jerry R. Green
Compensatory Transfers in Two-Player Decision Problems
Abstract | Paper
This paper presents an axiomatic characterization of a family of solutions to two-player quasi-linear social choice problems. In these problems the players select a single action from a set available to them. They may also transfer money between themselves. The solutions form a one-parameter family, where the parameter is a nonnegative number, t. The solutions can be interpreted as follows: Any efficient action can be selected. Based on this action, compute for each player a "best claim for compensation". A claim for compensation is the difference between the value of an alternative action and the selected efficient action, minus a penalty proportional to the extent to which the alternative action is inefficient. The coefficient of proportionality of this penalty is t. The best claim for compensation for a player is the maximum of this computed claim over all possible alternative actions. The solution, at the parameter value t, is to implement the chosen efficient action and make a monetary transfer equal to the average of these two best claims. The characterization relies on three main axioms. The paper presents and justifies these axioms and compares them to related conditions used in other bargaining contexts. In Nash Bargaining Theory, the axioms analagous to these three are in conflict with each other. In contrast, in the quasi-linear social choice setting of this paper, all three conditions can be satisfied simultaneously.

2016. John Y. Campbell and Tuomo Vuolteenaho
Bad Beta, Good Beta
Abstract | Paper
This paper explains the size and value “anomalies” in stock returns using an economically motivated two-beta model. We break the CAPMbeta of a stock with the market portfolio into two components, one reflecting news about the market’s future cash flows and one reflecting news about the market’s discount rates. Intertemporal asset pricing theory suggests that the former should have a higher price of risk; thus beta, like cholesterol, comes in “bad” and “good” varieties. Empirically, we find that value stocks and small stocks have considerably higher cash-flow betas than growth stocks and large stocks, and this can explain their higher average returns. The poor performance of the CAPMsince 1963 is explained by the fact that growth stocks and high-past-beta stocks have predominantly good betas with low risk prices.

2017. Edward L. Glaeser
Reinventing Boston: 1640-2003
Abstract | Paper
The three largest cities in colonial America remain at the core of three of America’s largest metropolitan areas today. This paper asks how Boston has been able to survive despite repeated periods of crisis and decline. Boston has reinvented itself three times: in the early 19th century as the provider of seafaring human capital for a far flung maritime trading and fishing empire, in the late 19th century as a factory town built on immigrant labor and Brahmin capital, and finally in the late 20th century as a center of the information economy. In all three instances, human capital—admittedly of radically different forms—provided the secret to Boston’s rebirth. The history of Boston suggests that a strong base of skilled workers is a more reliable source of long-run urban health.

2018. Jeremy Atack, Fred Bateman and Robert A. Margo
Capital Deepening in United States Manufacturing, 1850-1880
Abstract | Paper
Establishment-level data are used to study capital deepening – increases in the capital-output ratio – in U.S. manufacturing from 1850 to 1880. In both nominal and real terms, the aggregate capital-output ratio rose substantially over the period. Capital deepening is shown to be especially important in the larger firms and was associated with the diffusion of inanimate power. Although capital deepening implies a declining average product of capital, rates of return were not necessarily falling if capital’s share was increasing. However, there is strong evidence that returns did, in fact, decline.

2019. Andrei Shleifer and Daniel Treisman
A Normal Country
Abstract | Paper
During the 1990s, Russia underwent an extraordinary transformation from a communist dictatorship to a multi-party democracy, from a centrally planned economy to a market economy, and from a belligerent adversary of the West to a cooperative partner. Yet a consensus in the US circa 2000 viewed Russia as a disastrous and threatening failure, and the 1990s as a decade of catastrophe for its citizens. Analyzing a variety of economic and political data, we demonstrate a large gap between this perception and the facts. In contrast to the common image, by the late 1990s Russia had become a typical middle- income capitalist democracy.

2020. Edward L. Glaeser, Joseph Gyourko and Raven Saks
Why is Manhattan So Expensive? Regulation and the Rise in House Prices
Abstract | Paper
In Manhattan and elsewhere, housing prices have soared over the 1990s. Rising incomes, lower interest rates, and other factors can explain the demand side of this increase, but some sluggishness on the supply of apartment buildings also is needed to account for the high and rising prices. In a market dominated by high rises, the marginal cost of supplying more space is reflected in the cost of adding an extra floor to any new building. Home building is a highly competitive industry with almost no natural barriers to entry, yet prices in Manhattan currently appear to be more than twice their supply costs. We argue that land use restrictions are the natural explanation of this gap. We also present evidence consistent with our hypothesis that regulation is constraining the supply of housing so that increased demand leads to much higher prices, not many more units, in a number of other high price housing markets across the country.

2021. Susanto Basu, John G. Fernald, Nicholas Oulton and Sylaja Srinivasan
The Case of the Missing Productivity Growth: Or, Does Information technology explain why productivity accelerated in the United States but not the United Kingdom?
Abstract | Paper
We argue that unmeasured investments in intangible organizational capital—associated with the role of information and communications technology (ICT) as a ‘general purpose technology’—can explain the divergent U.S. and U.K. TFP performance after 1995. GPT stories suggest that measured TFP should rise in ICT-using sectors, perhaps with long lags. Contemporaneously, investments in ICT may in fact be associated with lower TFP as resources are diverted to reorganization and learning. In both the U.S. and U.K., we find a strong correlation between ICT use and industry TFP growth. The U.S. results, in particular, are consistent with GPT stories: the TFP acceleration was located primarily in ICT-using industries and is positively correlated with industry ICT capital growth from the 1980s and early 1990s. Indeed, as GPT stories suggest, controlling for past ICT growth, industry TFP growth appears negatively correlated with increases in ICT capital services in the late 1990s. A somewhat different picture emerges for the U.K. TFP growth does not appear correlated with lagged ICT capital growth. But TFP growth in the late 1990s is strongly and positively associated with the growth of ICT capital services, while being strongly and negatively associated with the growth of ICT investment.

2022. Ariel Pakes
Common Sense and Simplicity in Empirical Industrial Organization
Abstract | Paper
This paper is a revised version of a keynote address delivered at the inaugural International Industrial Organization Conference in Boston, April 2003. I argue that new econometric tools have facilitated the estimation of models with realistic theoretical underpinnings, and because of this, have made empirical I.O. much more useful. The tools solve computational problems thereby allowing us to make the relationship between the economic model and the estimating equations transparent. This, in turn, enables us to utilize the available data more e ectively. It also facilitates robustness analysis and clarifies the assumptions needed to analyze the causes of past events and/or make predictions of the likely impacts of future policy or environmental changes. The paper provides examples illustrating the value of simulation for the estimation of demand systems and of semiparametrics for the estimation of entry models.

2023. Edward L. Glaeser
Psychology and the Market
Abstract | Paper
Prospect theory, loss aversion, mental accounts, hyperbolic discounting, cues, and the endowment effect can all be seen as examples of situationalism— the view that people isolate decisions and overweight immediate aspects of the situation relative to longer term concerns. But outside of the laboratory, emotionally-powerful situational factors— frames, social influence, mental accounts— are almost always endogenous and often the result of self-interested entrepreneurs. As such, laboratory work and, indeed, psychology more generally, gives us little guidance as to market outcomes. Economics provides a stronger basis for understanding the supply of emotionally-relevant situational variables. Paradoxically, the rise of situationalism actually increases the relative importance of economics.

2024. Gene M. Grossman, Elhanan Helpman and Adam Szeidl
Optimal Integration Strategies for the Multinational Firm
Abstract | Paper
We examine integration strategies of multinational firms that face a rich array of choices of international organization. Each firm in an industry must provide headquarter services from its home country, produce intermediate inputs, and assemble the intermediate goods into final products. Both production of intermediate goods and assembly can be performed at home, in another “Northern” country, in the low-wage “South,” or in several of these locations. We study the equilibrium choices of firms that differ in productivity (and thus size), focusing on the role of industry characteristics such as the fixed costs of foreign subsidiaries, the cost of transporting intermediate and final goods,and the share of the consumer market that resides in the South in determining optimal integration strategies.

2025. Edward L. Glaeser and Albert Saiz
The Rise of the Skilled City
Abstract | Paper
For more than a century, educated cities have grown more quickly than comparable cities with less human capital. This fact survives a battery of other control variables, metropolitan area fixed effects and tests for reverse causality. We also find that skilled cities are growing because they are becoming more economically productive (relative to less skilled cities), not because these cities are becoming more attractive places to live. Most surprisingly, we find evidence suggesting that the skills-city growth connection occurs mainly in declining areas and occurs in large part because skilled cities are better at adapting to economic shocks. As in Schultz (1964), skills appear to permit adaptation.

2026. Williams J. Collins and Robert A. Margo
The Labor Market Effects of the 1960s Riots
Abstract | Paper
Between 1964 and 1971, hundreds of riots erupted in American cities, resulting in large numbers of injuries, deaths, and arrests, as well as in considerable property damage that was concentrated in predominantly black neighborhoods. There have been few studies of a systematic, econometric nature that examine the impact of the riots on the relative economic status of African Americans, or on the cities and neighborhoods in which the riots took. We present two complementary empirical analyses. The first uses aggregate, city-level data on income, employment, unemployment, and the area’s racial composition from the published volumes of the federal censuses. We estimate the “riot effect” by both ordinary least squares and two-stage least squares. The second empirical approach uses individual-level census data from the Integrated Public Use Microdata Series for 1950, 1970, and 1980. The findings suggest that the riots had negative effects on blacks’ income and employment that were economically significant and that may have been larger in the long run (1960-1980) than in the short run (1960- 1970). We view these findings as suggestive rather than definitive for two reasons. First, the data are not detailed enough to identify the precise mechanisms at work. Second, the wave of riots may have had negative spillover effects to cities that did not experience severe riots; if so, we would tend to underestimate the riots’ overall effect.

2027. Owen A. Lamont and Jeremy C. Stein
Aggregate Short Interest and Market Valuations
Abstract | Paper
We examine some basic data on the evolution of aggregate short interest, both during the dot-com era, and at other times in history. Total short interest moves in a countercyclical fashion. For example, short interest in NASDAQ stocks actually declines as the NASDAQ index approaches its peak. Moreover, this decline does not seem to reflect a substitution away from outright short-selling and towards put options, as the ratio of put-to-call volume displays the same countercyclical tendency. The evidence suggests that: i) arbitrageurs are reluctant to bet against aggregate mispricings; and ii) short-selling does not play a particularly helpful role in stabilizing the overall stock market.

2028. Alberto Alesina and Eliana La Ferrara
Ethnic Diversity and Economic Performance
Abstract | Paper
We survey and asses the literature on the positive and negative e?ects of ethnic diversity on economic policies and outcomes. Our focus is on countries, on cities in developed countries (the US) and on villages in developing countries. We also consider the endogenous formation of political jurisdictions and we highlight several open issues in need of further research.