HIER 2006 Abstracts
2099. Rustam Ibragimov and Donald J. Brown
Sign Tests for Dependent Observations
Abstract | Paper
The present paper introduces new sign tests for testing equality of conditional distributions of two (arbitrary) adapted processes as well as for testing conditionally symmetric martingale-difference assumptions. Our analysis is based on results that demonstrate randomization over ties in sign tests for equality of conditional distributions of two adapted sequences produces a stream of i.i.d. symmetric Bernoulli random variables. This reduces the problem of estimating the critical values of the tests to computing the quantiles or moments of Binomial or normal distributions. A similar proposition holds for randomization over zero values of three-valued random variables in a conditionally symmetric martyingale-difference sequence.
2100. Edward L. Glaeser and Bryce A. Ward
Myths and Realities of American Political Geography
Abstract | Paper
The division of America into red states and blue states misleadingly suggests that states are split into two camps, but along most dimensions, like political orientation, states are on a continuum. By historical standards, the number of swing states is not particularly low, and America’s cultural divisions are not increasing. But despite the flaws of the red state/blue state framework, it does contain two profound truths. First, the heterogeneity of beliefs and attitudes across the United States is enormous and has always been so. Second, political divisions are becoming increasingly religious and cultural. The rise of religious politics is not without precedent, but rather returns us to the pre-New Deal norm. Religious political divisions are so common because religious groups provide politicians the opportunity to send targeted messages that excite their base.
2101. Randall Morck
Corporations
Abstract | Paper
A corporation is an artificial person created for an economic purpose, as described in various aspects of the Theory of the Firm. Recent historical and comparative research shows that corporations in most countries come in groups, each controlled by a single principal. This has implications for various “theories of the firm”. The perception that firms ought to be run to maximize shareholder value, though commonplace in financial economics, is also problematic in application.
2102. Minyuan Zhao, Kathy Fogel, Randall Morck and Bernard Yeung
Trade Liberalization and Institutional Change
Abstract | Paper
Opening up to global trade and investment is often thought to trigger institutional improvement by raising the expected benefits of institutional reform and reducing incumbents' incentives and ability to preserve the status quo. However, recent experience is not entirely consistent with this conventional wisdom. We suggest an explanation based on variation across countries in firms’ reliance on ambient institutions. Large, well established, or state controlled firms depend less on an economy’s institutions than do small, incipient, or purely private sector firms. Multinational firms likewise can use their global organizations to sidestep weak local institutions. Firm heterogeneity of this sort can thus contribute to markedly different institutional responses to liberalization. Our framework also suggests that institutional development might occur in stages. In an economy whose basic institutions are sound, individuals rationally invest in entrepreneurial capability and firms rationally invest less in institution substitutes. Economies with firms that rely more on ambient institutions or with more potential entrants who would rely on those institutions are more likely to experience further institutional improvement following accession to the global economy. Economies with fewer firms or potential entrants dependent on sound institutions, in acceding to the global economy, may exhibit scant institutional improvement, and perhaps even institutional deterioration. Political rent-seeking is not necessary for the latter outcome, but expands the range of conditions under which it ensues.
2103. Randall Morck and Bernard Yeung
Purifying Japan's Banks: Issues and Implications
Abstract | Paper
We use a simple real options framework and empirical data to establish that although Japanese banks hold borrowers’ shares, their interest is more aligned as a contractual claimant than a residual claimant of corporations. We then explain why the Japanese model of corporate governance was useful during the 'catching up' growth of that country's postwar reconstruction decades, but became problematic subsequently. The interests of shareholders, creditors, workers, and managers are more readily aligned because such growth entails investment in known-technology physical capital- intensive projects with highly predictable cash flows. Once on the technological frontier, 'keeping up' growth requires risk taking and a tolerance for 'creative destruction'. This is better accommodated by entrusting corporate governance to firms' true residual claimants, their shareholders.
2104. Rustam Ibragimov and Johan Walden
The Limits of Diversification When Losses May Be Large
Abstract | Paper
Recent results in value at risk analysis show that, for extremely heavy-tailed risks with unbounded distribution support, diversification may increase value at risk, and that, generally, it is difficult to construct an appropriate risk measure for such distributions. We further analyze the limitations of diversification for heavy-tailed risks. We provide additional insight in two ways. First, we show that similar nondiversification results are valid for a large class of risks with bounded support, as long as the risks are concentrated on a sufficiently large interval. The required length of the support depends on the number of risks available and on the degree of heavy-tailedness. Second, we relate the value at risk approach to more general risk frameworks. We argue that in financial markets where the number of assets is limited compared with the (bounded) distributional support of the risks, unbounded heavy-tailed risks may provide a reasonable approximation. We suggest that this type of analysis may have a role in explaining various types of market failures in markets for assets with possibly large negative outcomes.
Thou Shall Not Diversify: Why :Two of every Sort"?
Abstract | Paper
The present paper sheds a new light on the notorious question in the evolutionary biology of why the modern species exhibit only the asexual and binary mating systems, with the clear dominance of the latter over the former. We present an in-depth study of the intertemporal propagation of the fundamental distributional properties of phenotypes in general polygenic multi-gender inheritance models with sex- and time-dependent heritability. We further analyze the implications of these models under thick-tailedness of traits' initial distributions. We obtain the results that demonstrate that under an arbitrary multi-sex mating system with k genders, the organism's switching to a more uniform mode of heritability leads to an increase in peakedness and concentration of traits with not extremely heavy-tailed initial distributions in its population in all the future periods. However, the decrease in the diversity of the parameters responsible for the different sexes' genetical contributions to the next period's offspring leads to an increase in concentration and peakedness of extremely long-tailed traits in all future generations. From these results it follows that switching to an inhertiance system with greater diversity in heritability coefficients and, thus, an increase in the number of genders under symmetric heritability, is advantageous in the case of extremely long-tailed traits that have negative effects on the population's fitness (say, human medical or behavioral disorders for which inheritance is significant). Such a switching or increase in the number of genders slows down or completely stops the intertemporal spread of the extremely thick-tailed negative traits in the population. On the other hand, a decrease in the number of genders in the symmetric multi-sex inheritance system and, more generally switching to less diverse heritability parameters is advantageous in the case of not extremely thick-tailed positive traits (e.g., the trait of intelligence). Our theoretical results demonstrate that the intertemporal propagation of distributional properties of traits is, to a large extent, responsible for the dominance of the asexual and binary mating systems in nature. Namely, from the results obtained in the paper it follows that the switching between the asexual and binary inheritance mechanisms allows the population to achieve effectively a relatively fast decline (sharp concentration) of "bad" traits or a relatively quick spread (decrease of peakedness and concentration) of "good" traits, regardless of the distributional properties of the phenotypes in the initial period, in particular, regardless of the degree of heavy-tailedness of their initial densities. Furthermore, from the results it follows that, regardless of their initial distributional properties, the propagation of negative traits in a population with three or more genders can be prevented and the wide spread of positive phenotypes can be achieved immediately or in a relatively near future if the population switches to a mating system with only one of two genders. Given the high costs to species of developing and maintaining extra genders, this makes the asexual binary inheritance mechanisms advantageous comparing to other mating systems.
2106. Xavier Gabaix and Rustam Ibragimov
Log(Rank-1/2): A Simple Way to Improve the OLS Estimation of Tail Exponents
Abstract | Paper
A popular way to estimate a Pareto exponent is to run an OLS regression: log (Rank) = c - blog (Size), and take b as an estimate of the Pareto exponent. Unfortunately, this procedure is strongly biased in small samples. We provide a simple practical remedy for this bias, and argue that, if one wants to use an OLS regression, one should use the Rank -1/2, and run log (Rank- 1/2) = c-b log (Size). The shift of 1/2 is optimal, and cancels the bias to a leading order. The standard error on the Pareto exponent is not the OLS standard error, but is asymptotically (2/n)^{1/2}b. To obtain this result, we provide asymptotic expansions for the OLS estimate in such log-log rank-size regression with arbitrary shifts in the ranks. The arguments for the asymptotic expansions rely on strong approximations to martingales with the optimal rate and demonstrate that martingale convergence methods provide a natural and conceptually simple framework for deriving the asymptotics of the tail index estimates using the log-log rank-size regressions.
2107. Laurent E. Calvet, John Y. Campbell and Paolo Sodini
Down or Out: Assessing the Welfare Costs of Household Investment Mistakes
Abstract | Paper
This paper investigates the efficiency of household investment decisions in a unique dataset containing the disaggregated wealth and income of the entire population of Sweden. The analysis focuses on two main sources of inefficiency in the financial portfolio: underdiversification of risky assets (“down”) and nonparticipation in risky asset markets (“out”). We find that while a few households are very poorly diversified, the cost of diversification mistakes is quite modest for most of the population. For instance, a majority of participating Swedish households are sufficiently diversified internationally to outperform the Sharpe ratio of their domestic stock market. We document that households with greater financial sophistication tend to invest more efficiently but also more aggressively, so the welfare cost of portfolio inefficiency tends to be greater for these households. The welfare cost of nonparticipation is smaller by almost one half when we take account of the fact that nonparticipants would be unlikely to invest efficiently if they participated in risky asset markets.
2108. Alberto Alesina, Silvia Ardagna, and Francesco Trebbi
Who adjusts and when? On the political economy of reforms
Abstract | Paper
Why do countries delay stabilizations of large and increasing budget deficits and inflation? And what explains the timing of reforms? We use the war of attrition model as a guidance for our empirical study on a vast sample of countries. We find that stabilizations are more likely to occur when time of crisis occur, at the beginning of term of office of a new government, in countries with "strong" governments, (i.e. presidential systems and unified governments with a large majority of the party in office), and when the executive faces less constraints. The role of external inducements like IMF programs has at best a weak effect, but problem of reverse causality are possible.
2109. Edward L. Glaeser and Joshua D. Gottlieb
Urban Resurgence and the Consumer City
Abstract | Paper
Cities make it easier for humans to interact, and one of the main advantages of dense, urban areas is that they facilitate social interactions. This paper provides evidence suggesting that the resurgence of big cities in the 1990s is due, in part, to the increased demand for these interactions and due to the reduction in big city crime, which had made it difficult for urban residents to enjoy these social amenities. However, while density is correlated with consumer amenities, we show that it is not correlated with social capital and that there is no evidence that sprawl has hurt civic engagement.
2110. N. Gregory Mankiw
A Letter to Ben Bernanke
Abstract | Paper
This paper discusses five questions the incoming chairman of the Federal Reserve must ponder as he assumes his new post. How important are monetary rules? Should the Fed adopt inflation targeting? Should he be free with his opinions? Should he be a high-profile public figure? Is it more important to be good or lucky?
2111.N. Gregory Mankiw amd Ricardo Reis
Pervasive Stickiness
Abstract | Paper
This paper explores a macroeconomic model of the business cycle in which stickiness of information is pervasive. We start from a familiar benchmark classical model and add to it the assumption that there is sticky information on the part of consumers, workers, and firms. We evaluate the model against three key facts that describe shortrun fluctuations: the acceleration phenomenon, the smoothness of real wages, and the gradual response of real variables to shocks. We find that pervasive stickiness is required to fit the facts. We conclude that models based on stickiness of information offer the promise of fitting the facts on business cycles while adding only one new plausible ingredient to the classical benchmark.
2112. Drew Fudenberg and David K. Levine
A Dual Self Model of Impulse Control
Abstract | Paper
We propose that a simple “dual-self” model gives a unified explanation for several empirical regularities, including the apparent time-inconsistency that has motivated models of hyperbolic discounting and Rabin’s paradox of risk aversion in the large and small. The model also implies that self-control costs imply excess delay, as in the O’Donoghue and Rabin models of hyperbolic utility, and it explains experimental evidence that increased cognitive load makes temptations harder to resist. Finally, the reduced form of the base version of our model is consistent with the Gul-Pesendorfer axioms.
Learning and Belief Based Trade
Abstract | Paper
We use the theory of learning in games to show that no-trade results do not require that gains from trade are common knowledge nor that play is a Nash equilibrium.
2114. Drew Fudenberg and David K. Levine
Superstition and Rational Learning
Abstract | Paper
We argue that some but not all superstitions can persist when learning is rational and players are patient, and illustrate our argument with an example inspired by the code of Hammurabi. The code specified an “appeal by surviving in the river” as a way of deciding whether an accusation was true, so it seems to have relied on the superstition that the guilty are more likely to drown than the innocent. If people can be easily persuaded to hold this superstitious belief, why not the superstitious belief that the guilty will be struck dead by lightning? We argue that the former can persist but the latter cannot by giving a partial characterization of the outcomes that arise as the limit of steady states with rational learning as players become more patient. These “subgame-confirmed Nash equilibria” have self-confirming beliefs at information sets reachable by a single deviation. According to this theory a mechanism that uses superstitions two or more steps off the equilibrium path, such as “appeal by surviving in the river,” is more likely to persist than a superstition where the false beliefs are only one step off of the equilibrium path.
2115. Alberto Alesina, William Easterly and Janina Matuszeski
Artificial States
Abstract | Paper
Artificial states are those in which political borders do not coincide with a division of nationalities desired by the people on the ground. We propose and compute for all countries in the world two new measures of the degree to which states are artificial. One is based on measuring how borders split ethnic groups into two separate adjacent countries. The other measures how straight land borders are, under the assumption the straight land borders are more likely to be artificial. We then show that these two measures seem to be highly correlated with several measures of political and economic success.
2116. Rustam Ibragimov and Johan Walden
Portfolio Diversification Under Local, Moderate and Global Deviations From Power Laws
Abstract | Paper
This paper focuses on the analysis of portfolio diversification for a wide class of nonlinear transformations of heavy-tailed risks. We show that diversification of a portfolio of nonlinear transformations of thick-tailed risks increases riskiness if expectations of these functions are infinite. In addition, coherency of the value at risk measure is always violated for such portfolios. On the contrary, for nonlinearly transformed heavy-tailed risks with finite expectations, the stylized fact that diversification is preferable continues to hold. Moreover, in the latter setting, the value of risk is a coherent measure of risk. The framework of transformations of long-tailed random variables includes many models with Pareto-type distributions that exhibit local, moderate and global deviations from power tails in the form of additional slowly varying or exponential factors. This leads to a refined understanding of under what distributional assumptions diversification increases riskiness.
2117. Alberto Alesina and Paola Giuliano
Divorce, fertility and the shot gun marriage
Abstract | Paper
Using the birth certificates data from the Vital Statistics of the USA between 1968 and 1999, we construct state level panel data of different measures of fertility and examine the change in divorce laws. Total fertility declined in states that introduced unilateral divorce, which makes dissolution of marriage easier. Most of this effect is due to a decline of out-of-wedlock fertility. We suggest an explanation (and provide supportive evidence for it) based upon the effect of divorce laws on the probability of entering and exiting marriage. Women planning to have children marry more easily with an easier “exit option” from marriage. Thus, more children are born in the first years of marriage, while the total marital fertility does not change, probably as a result of an increase in divorces and marital instability. The effect of changes in divorce laws is greater among whites than African Americans.
2118. Elhanan Helpman
Trade, FDI, and the Organization of Firms
Abstract | Paper
New developments in the world economy have triggered research designed to better understand the changes in trade and investment patterns, and the reorganization of production across national borders. Although traditional trade theory has much to offer in explaining parts of this puzzle, other parts required new approaches. Particularly acute has been the need to model alternative forms of involvement of business firms in foreign activities, because organizational change has been central in the transformation of the world economy. This paper reviews the literature that has emerged from these efforts. The theoretical refinements have focused on the individual firm, studying its choices in response to its own characteristics, the nature of the industry in which it operates, and the opportunities afforded by foreign trade and investment. Important among these choices are organizational features, such as sourcing strategies. But the theory has gone beyond the individual firm, studying the implications of firm behavior for the structure of industries. It provides new explanations for trade structure and patterns of FDI, both within and across industries, and has identified new sources of comparative advantage.
2119.Gene M. Grossman and Elhanan Helpman
Separation of Powers and the Budget Process
Abstract | Paper
We study budget formation in a model featuring separation of powers. In our model, the legislature designs a budget bill that can include a cap on total spending and ear- marked allocations to designated public projects. Each project provides random benefits to one of many interest groups. The legislature can delegate spending decisions to the executive, who can observe the productivity of all projects before choosing which to fund. However, the ruling coalition in the legislature and the executive serve different constituencies, so their interests are not perfectly aligned. We consider settings that differ in terms of the breadth and overlap in the constituencies of the two branches, and asso- ciate these with the political systems and circumstances under which they most naturally arise. Earmarks are more likely to occur when the executive serves broad interests, while a binding budget cap arises when the executive's constituency is more narrow than that of the powerful legislators.
2120. N. Gregory Mankiw and Phillip Swagel
The Politics and Economics of Offshore Outsourcing
Abstract | Paper
This paper reviews the political uproar over offshore outsourcing connected with the release of the Economic Report of the President (ERP) in February 2004, examines the differing ways in which economists and non-economists talk about offshore outsourcing, and assesses the empirical evidence on the importance of offshore outsourcing in accounting for the weak labor market from 2001 to 2004. Even with important gaps in the data, the empirical literature is able to conclude that offshore outsourcing is unlikely to have accounted for a meaningful part of the job losses in the recent downturn or contributed much to the slow labor market rebound. The empirical evidence to date, while still tentative, actually suggests that increased employment in the overseas affiliates of U.S. multinationals is associated with more employment in the U.S. parent rather than less.
2121. N. Gregory Mankiw
The Macroeconomist as Scientist and Engineer
Abstract | Paper
This essay offers a brief history of macroeconomics, together with an evaluation of what has been learned over the past several decades. It is based on the premise that the field has evolved through the efforts of two types of macroeconomist—those who understand the field as a type of engineering and those who would like it to be more of a science. While the early macroeconomists were engineers trying to solve practical problems, macroeconomists have more recently focused on developing analytic tools and establishing theoretical principles. These tools and principles, however, have been slow to find their way into applications. As the field of macroeconomics has evolved, one recurrent theme is the interaction—sometimes productive and sometimes not— between the scientists and the engineers.
2122. Edward L. Glaeser
Researcher Incentives and Empirical Methods
Abstract | Paper
Economists are quick to assume opportunistic behavior in almost every walk of life other than our own. Our empirical methods are based on assumptions of human behavior that would not pass muster in any of our models. The solution to this problem is not to expect a mass renunciation of data mining, selective data cleaning or opportunistic methodology selection, but rather to follow Leamer’s lead in designing and using techniques that anticipate the behavior of optimizing researchers. In this essay, I make ten points about a more economic approach to empirical methods and suggest paths for methodological progress.
2123. Alberto Alesina and Joseph Zeira
Technology and Labor Regulations
Abstract | Paper
Many low skilled jobs have been substituted away for machines in Europe, or eliminated, much more so than in the US, while technological progress at the “top”, i.e. at the hightech sector, is faster in the US than in Europe. This paper suggests that the main difference between Europe and the US in this respect is their different labor market policies. European countries reduce wage flexibility and inequality through a host of labor market regulations, like binding minimum wage laws, permanent unemployment subsidies, firing costs, etc. Such policies create incentives to develop and adopt labor saving capital intensive technologies at the low end of the skill distribution. At the same time technical progress in the US is more skill biased than in Europe, since American skilled wages are higher.
2124. Edward L. Glaeser and Bryce A. Ward
The Causes and Consequences of Land Use Regulation: Evidence from Greater Boston
Abstract | Paper
Over the past 30 years, eastern Massachusetts has seen a remarkable combination of rising home prices and declining supply of new homes. The reductions in new supply don’t appear to reflect a real lack of land, but instead reflect a response to man-made restrictions on development. In this paper, we examine the land-use regulations in greater Boston. There has been a large increase in the number of new regulations, which differ widely over space. Few variables, other than historical density and abundant recreational water, reliably predict these regulations. High lot sizes and other regulations are associated with less construction. The regulations boost prices by decreasing density, but density levels seem far too low to maximize total land value.
2125. Edward L. Glaeser
The Political Economy of Warfare
Abstract | Paper
Warfare is enormously destructive, and yet countries regularly initiate armed conflict against one another. Even more surprisingly, wars are often quite popular with citizens who stand to gain little materially and may lose much more. This paper presents a model of warfare as the result of domestic political calculations. When incumbents have an edge in fighting wars, they may start wars even if those wars run counter to their country’s interests. Challengers are particularly likely to urge aggression when they are unlikely to come into power and when the gains from coming to power are large. Leaders who start wars will naturally try to create hatred by emphasizing the threat and despicable character of the rival country. Wars will be more common in dictatorships than in democracies both because dictators have stronger incentives to stay in power and because they have greater control over the media.
2126. Glenn Ellison, Drew Fudenberg and Lorens A. Imhof
Random matching in adaptive dynamics
Abstract | Paper
This paper studies the effect of randomness in per-period matching on the long-run outcome of non-equilibrium adaptive processes. If there are many matchings between each strategy revision, the randomness due to matching will be small; our question is when a very small noise due to matching has a negligible effect. We study two different senses of this idea, and provide sufficient conditions for each. The less demanding sense corresponds to sending the matching noise to zero while holding fixed all other aspects of the adaptive process. The second sense in which matching noise can be negligible is that it doesn’t alter the limit distribution obtained as the limit of the invariant distributions as an exogeneous “mutation rate” goes to zero. When applied to a model with mutations, the difference between these two senses is in the order of limits: the first sense asks for continuity of e.g. the ergodic distribution in the matching noise holding the mutation rate fixed, whereas the second sense asks for continuity of the limit distribution in the matching noise.
2127. Pol Antras and Elhanan Helpman
Contractual Frictions and Global Sourcing
Abstract | Paper
We generalize the Antràs and Helpman (2004) model of the international organization of production in order to accommodate varying degrees of contractual frictions. In particular, we allow the degree of contractibility to vary across inputs and countries. A continuum of firms with heterogeneous productivities decide whether to integrate or outsource the production of intermediate inputs, and from which country to source them. Final-good producers and their suppliers make relationship-specific investments which are only partially contractible, both in an integrated firm and in an arm’s-length relationship. We describe equilibria in which firms with different productivity levels choose different ownership structures and supplier locations, and then study the effects of changes in the quality of contractual institutions on the relative prevalence of these organizational forms. Better contracting institutions in the South raise the prevalence of offshoring, but may reduce the relative prevalence of FDI or foreign outsourcing. The impact on the composition of offshoring depends on whether the institutional improvement affects disproportionately the contractibility of a particular input. A key message of the paper is that improvements in the contractibility of inputs controlled by final-good producers have different effects than improvements in the contractibility of inputs controlled by suppliers.
© 2007 by the President and Fellows of Harvard College