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We use new, comprehensive micro data on oil fields to build and estimate a structural model of the oil industry embedded in a general equilibrium model of the world economy. In the model, firms that belong to Organization of the Petroleum Exporting Countries (OPEC) act as a cartel. The remaining firms are a competitive fringe. We use the model to study the macroeconomic impact of the advent of fracking. Fracking weakens the OPEC cartel, leading to a large long-run decline in oil prices. Fracking also reduces the volatility of oil prices in the long run because fracking firms can respond more quickly to changes in oil demand.

We develop a quantitative macroeconomic theory of input-saving technical change to analyze how markets economize on scarce natural resources, with an application to fossil fuel. We find that aggreg...

There is a scientific consensus that human activities, in the form of emissions of carbon dioxide into the atmosphere, cause global warming. These emissions mostly occur in the marketplace, that is, they are undertaken by private individuals and firms. Governments seeking to curb emissions thus need to design policies that influence market behavior in the direction of their goals. Economists refer to Pigou taxation as “the” solution here, since the case of global warming can be seen as a pure (negative) externality. We agree. However, given the reluctance of policymakers to agree with us, there is an urgent need to consider, and compare, suboptimal policies. In this paper, we look at one such instance: setting a global tax on carbon at the wrong level. How costly are different errors? Since there is much uncertainty about how much climate change there will be, and how damaging it is when it occurs, ex-post errors will most likely be made. We compare different kinds of errors qualitatively and quantitatively and find that policy errors based on over-pessimistic views on climate change are much less costly than those made based on over-optimism. This finding is an inherent feature of standard integrated assessment models, even though these models do not feature tipping points or strong linearities.

We build a three-state general equilibrium model of the aggregate labor market that features both standard labor supply forces and labor market frictions. Our model matches key features of the cyclical properties of employment, unemployment, and nonparticipation as well as those of gross worker flows across these three labor market states. Our key finding is that shocks to labor market frictions play a dominant role in accounting for labor market fluctuations. This is in contrast to the focus of the traditional RBC literature, which emphasized how employment fluctuations arise as a consequence of labor supply responses to price changes induced by TFP shocks.

We use an analytically tractable heterogeneous-agent (HANK) version of the standard New Keynesian model to show how the size of fiscal multipliers depends on i) the distribution of factor incomes, and ii) the source of nominal rigidities. With sticky prices but flexible wages, the standard representative-agent (RANK) model predicts large multipliers because profits fall after a fiscal stimulus and the resulting negative income effect makes the representative worker work harder. Our HANK model, where workers do not own stock and thus do not receive profit income, predicts smaller fiscal multipliers. In fact, they are smaller with sticky prices than with flexible prices. When wages are the source of nominal rigidity, in contrast, fiscal multipliers are close to one, independently of income heterogeneity and price stickiness. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

We formulate an economic time use model and add to it an epidemiological SIR block. In the event of a pandemic, households shift their leisure time from activities with a high degree of social interaction to activities with less, and also choose to work more from home. Our model highlights the different actions taken by young individuals, who are less severely affected by the disease, and by old individuals, who are more vulnerable. We calibrate our model to time use data from ATUS, employment data, epidemiological data, and estimates of the value of a statistical life. There are qualitative as well as quantitative differences between the competitive equilibrium and social planner allocation and, moreover, these depend critically on when a cure arrives. Due to the role played by social activities in people's welfare, simple indicators such as deaths and GDP are insufficient for judging outcomes in our economy.

We construct an integrated assessment model with multiple energy sources—two fossil fuels and green energy—and use it to evaluate ranges of plausible estimates for the climate sensitivity, as well as for the sensitivity of the economy to climate change. Rather than focusing explicitly on uncertainty, we look at extreme scenarios defined by the upper and lower limits given in available studies in the literature. We compare optimal policy with laissez faire, and we point out the possible policy errors that could arise. By far the largest policy error arises when the climate policy is overly passive; overly zealous climate policy (i.e., a high carbon tax applied when climate change and its negative impacts on the economy are very limited) does not hurt the economy much as there is considerable substitutability between fossil and nonfossil energy sources.

The absence of a trend in hours worked in the postwar United States is an exception: across countries and historically, hours fall steadily by a little below 0.5% per year. Are steadily falling hours consistent with a stable utility function over consumption and leisure under balanced growth of the macroeconomic aggregates? Yes. We fully characterize the class of such functions and thus generalize the well-known “balanced-growth preferences” that demand constant (as opposed to falling) long-run hours. Key to falling hours is an income effect (of steady productivity growth on hours) that slightly outweighs the substitution effect.

We present a tractable heterogeneous-agent version of the New Keynesian model that allows us to study the interaction between inequality and monetary policy. Though formulated as a precautionary-saving model à la Huggett–Aiyagari, its reduced form is a two-agent model with a highly concentrated wealth distribution. When prices are sticky and wages flexible, as in the textbook representative-agent model, monetary policy affects the distribution of consumption, but has no effect on output as workers choose not to change their hours worked in response to wage movements. This highlights a transmission mechanism of the textbook model that we find implausible: in response to a monetary stimulus, the representative worker’s labor supply is greatly affected by the profits she receives. First, the lower profits induced by higher wages raise labor supply through a wealth effect and, secondly, the mere presence of profits reduces the negative income effect of a wage rise. When wages are rigid, in contrast, our model exhibits plausible responses of output and hours worked to monetary policy shocks.

In Capital in the Twenty-First Century , Thomas Piketty uses what he calls “the second fundamental law of capitalism” to predict that capital-to-income ratios are poised to increase dramatically as economies’ growth rates fall during the twenty-first century. This law states that in the long run the capital-to-income ratio equals s=g, where s is the economy’s saving rate and g its growth rate. We argue that this law rests on a theory of saving that is hard to justify. First, it holds the net saving rate constant as growth falls, driving the gross savings rate to one as growth goes to zero. Second, it is inconsistent with both the textbook growth model and the theory of optimal saving: in both of these theories the net saving rate goes to zero as growth goes to zero. Third, both of these theories provide a reasonable fit to observed data on gross and net saving rates and growth rates in cross-country panel data, whereas Piketty’s does not. Finally, contrary to Piketty’s second law, both of these theories predict that capital-to-income ratios increase only modestly as growth falls.

We propose a new method for computing equilibria in heterogeneous-agent models with aggregate uncertainty. The idea relies on an assumption that linearization offers a good approximation; we share this assumption with existing linearization methods. However, unlike those methods, the approach here does not rely on direct derivation of first-order Taylor terms. It also does not use recursive methods, whereby aggregates and prices would be expressed as linear functions of the state, usually a very high-dimensional object (such as the wealth distribution). Rather, we rely merely on solving nonlinearly for a deterministic transition path: we study the equilibrium response to a single, small “MIT shock” carefully. We then regard this impulse response path as a numerical derivative in sequence space and hence provide our linearized solution directly using this path. The method can easily be extended to the case of many shocks and computation time rises linearly in the number of shocks. We also propose a set of checks on whether linearization is a good approximation. We assert that our method is the simplest and most transparent linearization technique among currently known methods. The key numerical tool required to implement it is value-function iteration, using a very limited set of state variables. This article is part of a Special Issue entitled “Fiscal and Monetary Policies”.

We build a hybrid model of the aggregate labor market that features both standard labor supply forces and frictions in order to study the cyclical properties of gross worker flows across the three labor market states: employment, unemployment, and nonparticipation. Our parsimonious model is able to capture the key features of the cyclical movements in gross worker flows. Despite the fact that the wage per efficiency unit is constant over time, intertemporal substitution plays an important role in shaping fluctuations in the participation rate. (JEL E24, E32, J22, J31, J64, J65)

We use new, comprehensive micro data on oil fields to build and estimate a structural model of the oil industry embedded in a general equilibrium model of the world economy. In the model, firms that belong to OPEC act as a cartel. The remaining firms are a competitive fringe. We use the model to study the macroeconomic impact of the advent of fracking. Fracking weakens the OPEC cartel, leading to a large long-run decline in oil prices. Fracking also reduces the volatility of oil prices in the long run because fracking firms can respond more quickly to changes in oil demand.

A large increase in government spending following resource discoveries often entails political risks, inefficient investments and increased volatility. Setting up a sovereign wealth fund with a cle ...

This paper employs the benchmark heterogeneous-agent model used in macroeconomics to examine drivers of the rise in wealth inequality in the U.S. over the last thirty years. Several plausible candidates are formulated, calibrated to data, and examined through the lens of the model. There is one main finding: by far the most important driver is the significant drop in tax progressivity that started in the late 1970s, intensified during the Reagan years, and then subsequently flattened out, with only a minor bounce back. The sharp observed increases in earnings inequality, the falling labor share over the recent decades, and potential mechanisms underlying changes in the gap between the interest rate and the growth rate (Piketty's r - g story) all fall far short of accounting for the data.

This paper takes as given that (i) the burning of fossil fuel increases the carbon dioxide content in the atmosphere, which (ii) in turn leads to global heating and global climate change of a variety that, (iii) on net, is harmful to our welfare. To answer questions about the policy implications of this, a comprehensive and quantitative analysis of the two-way interaction between the economy, with its fossil fuel use, and the climate is necessary. In this paper, however, we focus on a particular aspect of this interaction: the role played by the industrial organization in the oil-producing sector of the world. Without a clear understanding of the world market for oil, the consequences of taxes and other policy instruments cannot be evaluated. Analyses of the world oil market that are based on perfect competition and a finite amount of oil typically predict (i) that the oil price satisfies the Hotelling rule, i.e., increases so that the rate of return on storing oil is equal to the return on the capital market, (ii) that oil consumption follows a decreasing path, and (iii) that extraction is sequential in the sense that sources with lower extraction costs are depleted before high-cost sources are used. All these predictions are problematic to reconcile with data. Our main point here is that the polar opposite case—where oil is supplied by a large agent with zero extraction costs who internalizes the effects of his decisions on all aggregates—seems useful for understanding historic and future developments in the oil market.

We analyse a Bewley-Huggett-Aiyagari incomplete-markets model with labour-market frictions. Consumers are subject to idiosyncratic employment shocks against which they cannot insure directly. The labour market has a Diamond-Mortensen-Pissarides structure: firms enter by posting vacancies and match with workers bilaterally, with match probabilities given by an aggregate matching function. Wages are determined through Nash bargaining. We also consider aggregate productivity shocks and a complete set of contingent claims conditional on this risk. We use the model to evaluate a tax-financed unemployment insurance scheme. Higher insurance is beneficial for consumption smoothing, but because it raises workers' outside option value, it discourages firm entry. We find that the latter effect is more potent for welfare outcomes; we tabulate the effects quantitatively for different kinds of consumers. We also demonstrate that productivity changes in the model—in steady state as well as stochastic ones—generate rather limited unemployment effects, unless workers are close to indifferent between working and not working; thus, recent findings are corroborated in our more general setting. Copyright , Wiley-Blackwell.

We investigate the welfare effects of eliminating business cycles in a model with substantial consumer heterogeneity. The heterogeneity arises from uninsurable and idiosyncratic uncertainty in preferences and employment status. We calibrate the model to match the distribution of wealth in U.S. data and features of transitions between employment and unemployment. In comparison with much of the literature, we find rather large effects. For our benchmark model, we find welfare effects that, on average across all consumers, are of a bit more than one order of magnitude larger than those computed by Lucas [Lucas Jr., R.E., 1987. Models of Business Cycles. Basil Blackwell, New York]. When we distinguish long- from short-term unemployment, long-term unemployment being distinguished by poor (and highly procyclical) employment prospects and low unemployment compensation, the average gain from eliminating cycles is as much as 1% in consumption equivalents. In addition, in both models, there are large differences across groups: very poor consumers gain a lot when cycles are removed (the long-term unemployed as much as around 30%), as do very rich consumers, whereas the majority of consumers—the “middle class”—sees much smaller gains from removing cycles. Inequality also rises substantially upon removing cycles.

This paper analyzes a model that features frictions, an operative labor supply margin, and incomplete markets. We first provide analytic solutions to a benchmark model that includes indivisible labor and incomplete markets in the absence of trading frictions. We show that the steady state levels of aggregate hours and aggregate capital stock are identical to those obtained in the economy with employment lotteries, while individual employment and asset dynamics can be different. Second, we introduce labor market frictions to the benchmark model. We find that the effect of the frictions on the response of aggregate hours to a permanent tax change is highly non-linear. We also find that there is considerable scope for substitution between "voluntary" and "frictional" nonemployment in some situations.

In this paper we study how a benevolent government that cannot commit to future policy should trade off the costs and benefits of public expenditure. We characterize and solve for Markov-perfect equilibria of the dynamic game between successive governments. The characterization consists of an inter-temporal first-order condition (a "generalized Euler equation") for the government, and we use it both to gain insight into the nature of the equilibrium and as a basis for computations. For a calibrated economy, we find that when the only tax base available to the government is capital income—an inelastic source of funds at any point in time—the government still refrains from taxing at confiscatory rates. We also find that when the only tax base is labour income the Markov equilibrium features less public expenditure and lower tax rates than the Ramsey equilibrium. Copyright 2008, Wiley-Blackwell.

For many kinds of capital, depreciation rates change systematically with the age of the capital. Consider an example that captures essential aspects of human capital, both regarding its accumulation and its depreciation: a worker obtains knowledge in period 0, then uses this knowledge in production in periods 1 and 2, and thereafter retires. Here, depreciation accelerates: it occurs at a 100% rate after period 2, and at a lower (perhaps zero) rate before that. The present paper analyzes the implications of non-constant depreciation rates for the optimal timing of taxes on capital income. The main finding is that under natural assumptions, the path of tax rates over time must be oscillatory. Oscillatory tax rates are optimal when depreciation rates accelerate with the age of the capital (as in the above example), and provided that the government can commit to the path of future tax rates but cannot apply different tax rates in a given year to different vintages of capital.

We discuss climate change and resource scarcity from the perspective of macroeconomic modeling and quantitative evaluation. Our focus is on climate change: we build a very simple “integrated assessment model,” ie, a model that integrates the global economy and the climate in a unified framework. Such a model has three key modules: the climate, the carbon cycle, and the economy. We provide a description of how to build tractable and yet realistic modules of the climate and the carbon cycle. The baseline economic model, then, is static but has a macroeconomic structure, ie, it has the standard features of modern macroeconomic analysis. Thus, it is quantitatively specified and can be calibrated to obtain an approximate social cost of carbon. The static model is then used to illustrate a number of points that have been made in the broad literature on climate change. Our chapter begins, however, with a short discussion of resource scarcity—also from the perspective of standard macroeconomic modeling—offering a dynamic framework of analysis and stating the key challenges. Our last section combines resource scarcity and the integrated assessment setup within a fully dynamic general equilibrium model with uncertainty. That model delivers positive and normative quantitative implications and can be viewed as a platform for macroeconomic analysis of climate change and sustainability issues more broadly.

The recent experience of a Great Recession has brought the effectiveness of fiscal policy back into focus. Fiscal multipliers do, however, vary greatly over time and place. Running VARs for a large number of countries, we document a strong correlation between wealth inequality and the magnitude of fiscal multipliers. To explain this finding, we develop a life-cycle, overlapping generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of OECD economies, including the distribution of wages and wealth, social security, taxes and debt and study the effects of changing policies and various forms of inequality on the fiscal multiplier. We find that the fiscal multiplier is highly sensitive to the fraction of the population who face binding credit constraints and also negatively related to the average wealth level in the economy. This explains the correlation between wealth inequality and fiscal multipliers.

Two approaches taken to the embodiment question are compared and discussed: quantitative theory and traditional growth accounting. The two approaches give very different estimates for the contribution of investment-specific technological advance to economic growth. Therefore, the approach taken matters. It is argued that the measures used in traditional growth accounting to gauge the importance of investment-specific technological progress have little economic content, unlike the measure obtained from quantitative theory.

Does capital-embodied technological change play an important role in shaping labour-market outcomes? To address this question, we develop a model with vintage capital and search-matching frictions where irreversible investment in new vintages of capital creates heterogeneity in productivity among firms, matched as well as vacant. We demonstrate that capital-embodied technological change reduces labour demand and raises equilibrium unemployment and unemployment durations. In addition, the presence of labour-market regulations (unemployment benefits, payroll taxes, and firing costs) exacerbates these effects. Thus, the model is qualitatively consistent with some key features of the European labour-market experience relative to that of the U.S.: it features a sharper rise in unemployment and a sharper fall in the vacancy rate and the labour share. A calibrated version of our model suggests that this technology—policy interaction could explain a sizeable fraction of the observed differences between the U.S. and Europe. Copyright 2007, Wiley-Blackwell.

We study a dynamic version of Meltzer and Richard's median-voter model where agents differ in wealth. Taxes are proportional to income and are redistributed as equal lump-sum transfers. Voting occurs every period and each consumer votes for the tax that maximizes his welfare. We characterize time-consistent Markov-perfect equilibria twofold. First, restricting utility classes, we show that the economy's aggregate state is mean and median wealth. Second, we derive the median-voter's first-order condition interpreting it as a tradeoff between distortions and net wealth transfers. Our method for solving the steady state relies on a polynomial expansion around the steady state.

We examine how technological change affects wage inequality and unemployment in a calibrated model of matching frictions in the labor market. We distinguish between two polar cases studied in the literature: a “creative destruction” economy, where new machines enter chiefly through new matches and an “upgrading” economy, where machines in existing matches are replaced by new machines. Our main results are: (i) these two economies produce very similar quantitative outcomes, and (ii) the total amount of wage inequality generated by frictions is very small. We explain these findings in light of the fact that, in the model calibrated to the US economy, both unemployment and vacancy durations are very short, i.e., the matching frictions are quantitatively minor. Hence, the equilibrium allocations of the model are remarkably close to those of a frictionless version of our economy where firms are indifferent between upgrading and creative destruction, and where every worker is paid the same market-clearing wage. These results are robust to the inclusion of machine-specific or match-specific heterogeneity into the benchmark model. (JEL: J41, J64, O33)

The success of the New Keynesian framework stems from its ability to match the aggregate responses to innovations in monetary policy and total factor productivity (TFP). Specifically, the model can account for negative responses of output to innovations in the policy rate and a negative response of employment to innovations in TFP. We reexamine the transmission channel of the textbook model and show that these successful results rely on the assumption that firm profits are redistributed to working households. We contrast the textbook model to a worker-capitalist model where profits are consumed by non-working capitalists. This modification renders employment and output unresponsive to monetary policy and employment unresponsive to TFP. The reason is that the income and substitution effects of changes in the wage level cancel when the worker receive income from wages alone. Given the empirically observed distribution of equity ownership and the VAR evidence on the business cycle behavior of profits, we argue that our results cast doubt on the transmission channel in the textbook model.

Political and economic transitions of non-market economies often go hand in hand. We propose an economic theory of this transition process, which highlights how the success of such a transition depends upon the policies chosen in the new democratic environment. In this paper, economic success is characterized by the continual adoption of new technology (and economic growth), which requires costly human capital investment. The political choice is whether to allow the adoption of new technology. As a non-market economy begins its transition, agents with human capital specific to a particular technology find it in their interest to vote against continued innovation. As such, the transition to a market economy can be choked off. Our theory has the following features: (i) an economic transition is associated with a substantial drop in output; (ii) it is in the interest of large groups in the population to resist laissez–faire, as factor payments equal marginal products in the post–reform economy; (iii) although the joint move to democracy and a market economy does make people better off, it is insufficient for the transition to be successful, as the number of agents with a vested interest against continued innovation grows; and (iv) a temporary\/ restriction on voting rights which ensures a laissez-faire regime is sufficient to produce long-run\/ prosperity. This restriction may not be only one capable of overcoming the anti–innovation interests. Other mechanisms such as supermajority rules on policy changes may also guarantee laissez–faire.

If the government cares more about workers than about capitalists and taxes capital income to finance redistribution to workers, how are inequality and capital accumulation affected in the long run? Assuming that the government cannot commit to future taxes, a time-consistent equilibrium – a differentiable subgame-perfect Markov equilibrium – is characterized. In this equilibrium, the current government in part uses the tax, via capital accumulation, to manipulate future governments into setting lower taxes. The equilibrium has substantially lower taxes on capital income than 100%, even though workers do not save and even though the weight on capitalists in government utility is negligible.

We analyze a general-equilibrium asset pricing model where a small subset of the consumers/investors have a short-run ‘‘urge to save’’. That is, their attitude toward consumption in the long run is a standard one F they do place zero weight on consumption far enough out in the future F but their short-run effective rates of discount may be negative. Our model, which is an elaboration on the framework proposed by Faruk Gul and Wolfgang Pesendorfer, does not feature time inconsistencies. Thus, we view consumers as fully rational, but subject to specific ‘‘internal frictions’’ in the form of temptation and self-control problems. The model nests the Mehra–Prescott model and we use it as a way of interpreting the wealth and asset pricing data. Some aspects of these data, we argue, can possibly be better understood using our model than the standard one. r 2002 Published by Elsevier Science B.V.

The recent experience of a Great Recession has brought the effectiveness of fiscal policy back into focus. Fiscal multipliers do, however, vary greatly over time and place. between wealth inequality and the magnitude of fiscal multipliers. To explain this finding, we develop a life-cycle, overlapping generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of OECD economies, including the distribution of wages and wealth, social security, taxes and debt and study the effects of changing policies and various forms of inequality on the fiscal multiplier. We find that the fiscal multiplier is highly sensitive to the fraction of the population who face binding credit constraints and also negatively related to the average wealth level in the economy. This explains the correlation between wealth inequality and fiscal multipliers.

The supply and price of skilled labor relative to unskilled labor have changed dramatically over the postwar period. The relative quantity of skilled labor has increased substantially, and the skill premium, which is the wage of skilled labor relative to that of unskilled labor, has grown significantly since 1980. Many studies have found that accounting for the increase in the skill premium on the basis of observable variables is difficult and have concluded implicitly that latent skill-biased technological change must be the main factor responsible. This paper examines that view systematically. We develop a framework that provides a simple, explicit economic mechanism for understanding skill-biased technological change in terms of observable variables, and we use the framework to evaluate the fraction of variation in the skill premium that can be accounted for by changes in observed factor quantities. We find that with capital-skill complementarity, changes in observed inputs alone can account for most of the variations in the skill premium over the last 30 years.

This is a quantitative investigation of the importance of technological change speci"c to new investment goods for postwar US aggregate #uctuations. A growth model that incorporates this form of technological change is calibrated to US data and simulated, using the relative price of new equipment to identify the process driving investmentspeci"c technology shocks. The analysis suggests that this form of technological change is the source of about 30% of output #uctuations. ( 2000 Elsevier Science B.V. All rights reserved.

We study a dynamic version of Meltzer and Richard's median-voter analysis of the size of government. Taxes are proportional to total income, and they are used for government consumption, which is exogenous, and for lump-sum transfers, whose size is chosen by electoral vote. Votes take place sequentially over time, and each agent votes for the policy that maximizes his equilibrium utility. We calibrate the model and its income and wealth distribution to match postwar U.S. data. This allows a quantitative assessment of the equilibrium costs of redistribution, which involves distortions to the labor-leisure and consumption-savings choices, and of its benefits for the decisive voter. We find that the total size of transfers predicted by our political-economy model is quite close to the size of transfers in the data.

How do movements in the distribution of income and wealth affect the macroeconomy? We analyze this question using a calibrated version of the stochastic growth model with partially uninsurable idiosyncratic risk and movements in aggregate productivity. Our main finding is that, in the stationary stochastic equilibrium, the behavior of the macroeconomic aggregates can be almost perfectly described using only the mean of the wealth distribution. This result is robust to substantial changes in both parameter values and model specification. Our benchmark model, whose only difference from the representative‐agent framework is the existence of uninsurable idiosyncratic risk, displays far less cross‐sectional dispersion and skewness in wealth than U.S. data. However, an extension that relies on a small amount of heterogeneity in thrift does succeed in replicating the key features of the wealth data. Furthermore, this extension features aggregate time series that depart significantly from permanent income behavior.