Research Database

This paper surveys implementation theory when players have incomplete or asymmetric information, especially in economic environments. After the basic problem is introduced, the theory of implementation is summarized. Some coalitional considerations for implementation problems are discussed. For economies with asymmetric information, cooperative games based on incentive compatibility constraints or Bayesian incentive compatible mechanisms are derived and examined.

Gali and Rabanal provide statistical evidence that, in their view, puts into question the real business-cycle paradigm in favor of the sticky-price paradigm. I demonstrate that their statistical procedure is easily misled in that they would reach the same conclusions even if their data had been simulated from an RBC model. I also demonstrate that sticky-price models do a poor job generating U.S.-like business cycles with only shocks to technology, the federal funds rate, and government consumption. This explains why Gali and Rabanal need large unobserved shocks to preferences and to the degree of monopoly power.

There is wide variation in the sizes of manufacturing plants, even within the most narrowly defined industry classifications used by statistical agencies. Standard theories attribute all such size differences to productivity differences. This paper develops an alternative theory in which industries are made up of large plants producing standardized goods and small plants making custom or specialty goods. It uses confidential Census data to estimate the parameters of the model, including estimates of plant counts in the standardized and specialty segments by industry. The estimated model fits the data relatively well compared with estimates based on standard approaches. In particular, the predictions of the model for the impacts of a surge in imports from China are consistent with what happened to U.S. manufacturing industries that experienced such a surge over the period 1997--2007. Large-scale standardized plants were decimated, while small-scale specialty plants were relatively less impacted.

We study the importance of international trade in structural change. Our framework has both productivity and trade cost shocks, and allows for non-unitary income and substitution elasticities. We calibrate our model to investigate South Korea’s structural change between 1971 and 2005. We find that the shock processes, propagated through the model’s two main transmission mechanisms, non-homothetic preferences and the open economy, explain virtually all of the evolution of agriculture and services labor shares, and the rising part of the hump-shape in manufacturing. Counterfactual exercises show that the role of the open economy is quantitatively important for explaining South Korea’s structural change.

The data show that an increase in government provided old-age pensions is strongly correlated with a reduction in fertility. What type of model is consistent with this finding? We explore this question using two models of fertility: one by Barro and Becker (1989), and one inspired by Caldwell (1978, 1982) and developed by Boldrin and Jones (2002). In Barro and Becker’s model parents have children because they perceive their children’s lives as a continuation of their own. In Boldrin and Jones’ framework parents procreate because children care about their parents’ utility, and thus provide them with old-age transfers. The effect of increases in government provided pensions on fertility in the Barro and Becker model is very small, whereas the effect on fertility in the Boldrin and Jones model is sizeable and accounts for between 55 and 65% of the observed Europe-U.S. fertility differences both across countries and across time.

Typical incomplete markets models in international economics make two assumptions. First, households are not able to fully insure themselves against country-specific shocks. Second, there is a representative household within each country, so that households are fully insured against idiosyncratic shocks. We assume instead that cross-household risk-sharing is limited within countries, but cross-country risk-sharing is complete. We consider two types of limited risk-sharing: domestically incomplete markets (DI) and private information-Pareto optimal (PIPO) risk-sharing. We show that the models imply distinct restrictions between the cross-sectional distributions of consumption and real exchange rates. We evaluate these restrictions using household-level consumption data from the United States and the United Kingdom. We show that the PIPO restriction fits the data well when households have a coefficient of relative risk aversion of around 5. The analogous restrictions implied by the representative agent model and the DI model are rejected at conventional levels of significance.

We establish that creditor beliefs regarding future borrowing can be self-fulfilling, leading to multiple equilibria with markedly different debt accumulation patterns. We characterize such indeterminacy in the Eaton-Gersovitz sovereign debt model augmented with long maturity bonds. Two necessary conditions for the multiplicity are: (i) the government is more impatient than foreign creditors, and (ii) there are deadweight losses from default; both are realistic and standard assumptions in the quantitative literature. The multiplicity is dynamic and stems from the self-fulfilling beliefs of how future creditors will price bonds; long maturity bonds are therefore a crucial component of the multiplicity. We introduce a third party with deep pockets to discuss the policy implications of this source of multiplicity and identify the potentially perverse consequences of traditional “lender of last resort” policies.

This paper studies the nature of business cycle variation in individual earnings risk using a confidential dataset from the U.S. Social Security Administration, which contains (uncapped) earnings histories for millions of individuals. The base sample is a nationally representative panel containing 10 percent of all U.S. males from 1978 to 2010. We use these data to decompose individual earnings growth during recessions into “between-group” and “within-group” components. We begin with the behavior of within-group shocks. Contrary to past research, we do not find the variance of idiosyncratic earnings shocks to be countercyclical. Instead, it is the left-skewness of shocks that is strongly countercyclical. That is, during recessions, the upper end of the shock distribution collapses—large upward earnings movements become less likely—whereas the bottom end expands—large drops in earnings become more likely. Thus, while the dispersion of shocks does not increase, shocks become more left-skewed and, hence, risky during recessions. Second, to study between-group differences, we group individuals based on several observable characteristics at the time a recession hits. One of these characteristics—the average earnings of an individual at the beginning of a business cycle episode—proves to be an especially good predictor of fortunes during a recession: prime-age workers that enter a recession with high average earnings suffer substantially less compared with those who enter with low average earnings (which is not the case during expansions). Finally, we find that the cyclical nature of earnings risk is dramatically different for the top 1 percent compared with all other individuals—even relative to those in the top 2 to 5 percent.

Today, monopolies inflict great harm on low- and middle-income Americans. One particularly pernicious way they harm them is by sabotaging low-cost products that are substitutes for the monopoly products. I'll argue that the U.S. housing crisis, legal crisis, and oral health crisis facing the low- and middle-income Americans are, in large part, the result of monopolies destroying low-cost alternatives in these industries that the poor would purchase. These results would not surprise those studying monopolies in the first half of the 20th century. During this period extensive evidence was developed showing monopolies engaging in these same activities and many others that harmed the poor. Models of monopoly were constructed by giants in economics and law, such as Henry Simons and Thurman Arnold, to explain these impacts of monopoly. These models are of sabotaging monopolies. Unfortunately, in the 1950s, the economics profession turned its back on this evidence, these models and these giants. It embraced the Cournot model of monopoly, that found in textbooks today. In this model the monopolist chooses its price, nothing more. Gone are the decisions on whether to sabotage substitutes or to employ any of the other weapons at the disposal of sabotaging monopolies. I'll call this Cournot monopoly the toothless monopoly. Using this model, the economics profession has concluded that the costs of monopoly are small. But the toothless monopoly model is ill-equipped to study the "costs of monopoly." By relying on it, the economics profession has made major errors in its study of monopoly.

In this paper, we examine various exchange rate regimes, paying particular attention to what difference the monetary-fiscal policy choices of governments make. The exchange rate may be market-determined or fixed, and if fixed, either cooperatively or by one government alone. Further, capital controls may or may not apply. Our most important result, quite general, we believe, is that absent capital controls the equilibrium exchange rate of the floating rate regime is indeterminate. It makes no sense to advocate floating rates and unfettered international borrowing and lending.

I develop an asset-pricing model in which financial assets are valued for their liquidity—the extent to which they are useful in facilitating exchange—as well as for being claims to streams of consumption goods. The implications for average asset returns, the equity-premium puzzle and the risk-free rate puzzle, are explored in a version of the model that nests the work of Mehra and Prescott (1985).

Many manufacturing industries, including the computer industry, have seen large increases in productivity growth rates and have experienced a reduction in average establishment size and a decrease in the variance of the sizes of plants. A vintage capital model is introduced where learning increases productivity on any given technology and firms choose when to adopt a new vintage. In the model, a rise in the rate of technological change leads to a decrease in both the mean and variance of the size distribution.

We look for the scale effects predicted by some theories of trade and growth based on the dynamic returns to scale that arise from learning by doing, investment in human capital, or development of new products. We find little empirical evidence of a relation between the growth rate of GDP per capita and the measures of scale implied by the theory. Restricting attention to the manufacturing sector, however, we find a significant relation between the growth rate of output per worker and the relevant scale variables. We also find that growth rates are significantly related to measures of intra-industry trade.

We examine the responses of prices and inflation to monetary shocks in an inventory-theoretic model of money demand. We show that the price level responds sluggishly to an exogenous increase in the money stock because the dynamics of households' money inventories leads to a partially offsetting endogenous reduction in velocity. We also show that inflation responds sluggishly to an exogenous increase in the nominal interest rate because changes in monetary policy affect the real interest rate. In a quantitative example, we show that this nominal sluggishness is substantial and persistent if inventories in the model are calibrated to match U.S. households' holdings of M2.

We develop a multicountry model in which default in one country triggers default in other countries. Countries are linked to one another by borrowing from and renegotiating with common lenders. Countries default together because by doing so they can renegotiate the debt simultaneously and pay lower recoveries. Defaulting is also attractive in response to foreign defaults because the cost of rolling over the debt is higher when other countries default. Such forces are quantitatively important for generating a positive correlation of spreads and joint incidence of default. The model can rationalize some of the recent economic events in Europe as well as the historical patterns of defaults, renegotiations, and recoveries across countries.

This paper presents a simple general equilibrium model of optimal taxation similar to that of Lucas and Stokey (1983), except that we let the government default on its debt. As a benchmark, we consider Ramsey equilibria in which the government can precommit its policies at the beginning of time. We then consider sustainable equilibria in which both government and private agent decision rules are required to be sequentially rational. We concentrate on trigger mechanisms which specify reversion to the finite horizon equilibrium after deviations by the government. The main result is that no Ramsey equilibrium with positive debt can be supported by such trigger mechanisms.

We develop a simple dynamic economic model of epidemic transmission designed to be consistent with widely used SIR biological models of the transmission of epidemics, while incorporating economic benefits and costs as well. Our main finding is that targeted testing and isolation policies deliver large welfare gains relative to optimal policies when these tools are not used. Specifically, we find that when testing and isolation are not used, optimal policy delivers a welfare gain equivalent to a 0.6% permanent increase in consumption relative to no intervention. The welfare gain arises because under the optimal policy, the planner engineers a sharp recession that reduces aggregate output by about 40% for about 3 months. This sharp contraction in economic activity reduces the rate of transmission and reduces cumulative deaths by about 0.1%. When testing policies are used, optimal policy delivers a welfare gain equivalent to a 3% permanent increase in consumption. The associated recession is milder in that aggregate output declines by about 15% and cumulative deaths are reduced by .3%. Much of this welfare gain comes from isolating infected individuals. When individuals who are suspected to be infected are isolated without any testing, optimal policy delivers a welfare gain equivalent to a 2% increase in permanent consumption.

This paper develops a simple model of sovereign debt in which defaulting nations are excluded from capital markets and regain access by making partial repayments. This is consistent with the historical evidence that defaulting countries return to international loan markets soon after a settlement, but after varying periods of exclusion.

We propose a definition of involuntary unemployment which differs from that traditionally used in implicit labor contract theory. We say that a worker is involuntarily unemployed if the marginal wage implied by the optimal contract exceeds the marginal rate of substitution between leisure and consumption. We construct a model where risk-neutral firms have monopoly power and show that such monopoly power is necessary for involuntary unemployment to arise in the optimal contract. We numerically compute examples and show that such unemployment occurs for a wide range of parameter values.

Are deflation and depression empirically linked? No, concludes a broad historical study of inflation and real output growth rates. Deflation and depression do seem to have been linked during the 1930s. But in the rest of the data for 17 countries and more than 100 years, there is virtually no evidence of such a link.