We develop a test of evolutionary change that incorporates a null hypothesis of homogeneity, which encompasses time invariance in the variance and autocovariance structure of residuals from estimated econometric relationships. The test framework is based on examining whether shifts in spectral decomposition between two frames of data are significant. Rejection of the null hypothesis will point not only to weak nonstationarity but to shifts in the structure of the second-order moments of the limiting distribution of the random process. This would indicate that the second-order properties of any underlying attractor set has changed in a statistically significant way, pointing to the presence of evolutionary change. A demonstration of the test's applicability to a real-world macroeconomic problem is accomplished by applying the test to the Australian Building Society Deposits (ABSD) model.

This paper introduces a method of optimization in infinite-horizon economies based on the theory of correspondences. The proposed approach allow us to study time-separable and non-time-separable dynamic economic models without resorting to fixed point theorems or transversality conditions. When our technique is applied to the standard time-separable model it provides an alternative and straightforward way to derive the common recursive formulation of these models by means of Bellman equations.

In this paper, we prove in terms of the prototype model of social common capital that the optimum conditions for sustainable processes of capital accumulation involving both private capital and social common capital coincide precisely with those for market equilibrium with the social common capital taxes at certain specific rates under the stationary expectations hypothesis concerning the future schedule of marginal productivity of capital of all kinds.

Dynamic spatial theory has been a fruitful approach to understanding economic phenomena involving time and space. However, several central questions still remain unresolved in this field. The identification of the social optimal allocation of economic activity across time and space is particularly problematic, not been ensured yet in economic growth. Developing a monotone method, we study the optimal solution of the spatial Ramsey model. Under fairly general assumptions, we prove the existence of unique social optimum. Considering a numerical implementation of our algorithm, we study the role played by capital mobility in the neoclassical growth environment. With capital irreversibility and economic openness, space allows for transitional dynamics. Moreover, in this context, capital mobility is beneficial as well in terms of social welfare and inequality. We also consider an application of our method to an extension of the spatial Ramsey model for optimal land-use planning.

Government shares in total output are characterized by significant variation across countries. I noticed a strong negative correlation between government consumption shares and the price of government services in terms of private consumption. Motivated by this empirical observation, I developed a neoclassical growth model with added government that is capable of matching the variation in government shares very closely using only relative prices. In addition, I provide empirical evidence showing that the relative price of government consumption increases with income, which is consistent with distortions prevailing in poor countries. These two observations combined imply that government shares tend to be higher in poorer countries.

This paper analyzes the impact of trade on the stability properties of trading countries and on stationary welfare. We consider a two-country two-good two-factor overlapping generations model where countries differ in terms of their technology. In the autarky equilibrium and the free-trade equilibrium, indeterminacy relies, under dynamic efficiency, on a capital intensive consumption good and intermediate values of the elasticity of intertemporal substitution in consumption. Opening the borders to trade can be a source of a global destabilizing effect. Indeed, considering a free-trade equilibrium in which one country is an exporter of the consumption good and the other country is an exporter of the investment good, indeterminacy can occur with trade even though the two countries are determinate in autarky. Finally, opening to trade increases the stationary welfare of the country that exports the investment good and deteriorates the one of the other country.

We consider a New-Keynesian model with financial and labor market frictions where firms borrowing is limited by the enforcement constraint. The wage is set in a bargaining process where the firm's shareholder and worker share the production surplus. As debt service is considered to be a part of production costs, firms borrow to reduce the surplus which allows to lower the wage. We study the model's response to financial shock under two Taylor-type interest rate rules: first one responds to inflation and borrowing, second one to inflation and unemployment. We have found that the second rule delivers better policy in terms of the welfare measure. Additionally, we show that the feedback on unemployment in this rule depends on the extent of workers' bargaining power.

We present a multiregional endogenous growth model in which forward-looking agents choose their regions to live in, in addition to consumption and capital accumulation paths. The spatial distribution of economic activity is determined by the interplay between production spillover effects and urban congestion effects. We characterize the global stability of the spatial equilibrium states in terms of economic primitives such as agents’ time preference and intra- and interregional spillovers. We also study how macroeconomic variables at the stable equilibrium state behave according to the structure of the spillover network.

We study an impact of the financial intermediation on economic growth. We assume the simple model of the economic growth in the form of an autonomous dynamical system with a financial sector represented by banks and real sector represented by households and firms. We assume that financial intermediation services are described by financial intermediation technology which is a function depending on the share of labor employed by banks. Investments realized by firms depend not only on savings accumulated by banks but also on financial intermediation technology. We obtain a three-dimensional dynamical system and analyze the existence of a saddle equilibrium in the growth process associated with financial intermediation. Using mathematical methods of dynamical systems, we analyze growth paths, and we study the stationary states of the system and their stability. We found that equilibrium is reached only by trajectories located on two submanifolds. The resulting analysis provides an insight into the saddle solution with a stable incoming separatrix lying on one of the invariant manifolds.

This paper analyzes the effect of the sectoral composition of government spending on the stability properties of a two-sector economy with a progressive tax structure. The results suggest that indeterminacy is more likely to occur if the fraction of government spending on consumption goods increases. This study also finds that, under progressive taxation, a sufficiently high public-consumption share is needed to generate indeterminacy. It is shown that, with the benchmark parameterization, a higher fraction of government spending on consumption goods needs to be implemented with a more progressive tax scheme to stabilize the economy. Moreover, it is emphasized that belief-driven economic fluctuations may indeed be a feature of the U.S. economy.

Current Population Survey (CPS) data over the period from 1994 to 2008 show that inflation has a positive effect on the residual wage dispersion. To explain this phenomenon, we introduce uncoordinated job searches into a general equilibrium monetary search framework. Our model shows that the uncoordinated job searches by unemployed workers give rise to an equilibrium, where a firm is matched with zero, one, or multiple job applicants. The ex post difference in matching probabilities generates a two-point wage dispersion among identical workers, when the Mortensen rule is implemented in the wage-determination process. In our model, inflation positively influences the wage dispersion directly through its impact on firm's real profit and indirectly through the effect of inflation that spills over from the goods market to the labor market. With reasonable parameter values, the calibrated model can account for most of the observed responses of residual wage dispersion to inflation.

In this paper, I study the effect that switching to a voucher system of educational finance has on the distribution of income. The model is calibrated to U.S. data, and simulated for two different forms of education finance: a voucher system and a completely private system of schools. All voucher policies considered result in welfare gains and reductions in income inequality. A private system entails a welfare loss and an increase in income inequality. The more important the peer group is to future income, the smaller the welfare gains and reductions in inequality associated with voucher systems, and the greater the welfare cost and increase in inequality associated with a private system.

If one drops the strong assumption that firms and households know all of the relevant parameters, and instead models agents as learning these parameters, the estimated parameters become random variables. Taking expectations several periods into the future may then involve taking the expectation of a product of random variables. Because the resulting problem is difficult, previous research has avoided it. This paper makes some progress using both analytical and numerical techniques. Focusing especially on consumption, we find that the resulting covariance terms could account for the well-documented empirical result that consumption displays excess sensitivity to lagged income. We show that a similar covariance effect could play a role in many widely used economic models.

The present paper studies the influence of variable labor utilization on local indeterminacy and expectations-driven fluctuations, in one-sector models with (nearly) constant returns to scale. It is shown that, in comparison to the configuration of constant input utilization, considering variable utilization reduces the actual possibilities of factor substitution and, consequently, the range of input substitution elasticities that are compatible with endogenous fluctuations. In particular, local indeterminacy and expectations-driven fluctuations occur only if utilization rates are sufficiently inelastic, whereas local determinacy prevails when utilization is highly elastic. However, accounting for the fact that variable utilization reduces the effective elasticity of capital/labor substitution leads us to argue that expectations-driven fluctuations are more plausible because they require larger elasticities of apparent input substitution. In contrast with the recent literature, the analysis does not rely on significantly increasing returns to scale in production. Accordingly, the results are not at variance with recent empirical studies emphasizing the importance of variable utilization and denying the evidence of large increasing returns.

This paper offers a reinterpretation of the Fed's time-varying implicit inflation target, based on two considerations. The first is that the need to alleviate the burden of distortionary taxation may justify the choice of a positive inflation rate. The second is based on compelling evidence that the degree of price and wage indexation falls with trend inflation. In fact, we find that a proper characterization of the joint evolution of fiscal variables and nominal rigidities has a strong impact on the Ramsey optimal policies, implying optimal inflation dynamics that are consistent with the observed evolution of U.S. trend inflation. By contrast, tax policies have been too lax, especially at the time of the controversial Bush tax cuts.

A key result in macroeconomics is the “time inconsistency of short-run optimal plans.” It is argued that inflationary bias results if central bankers do not precommit to a monetary policy rule. The macro literature, however, does not address the way in which board members arrive at the “optimal choice of inflation rate.” That is a matter of a micro subfield called social choice. If we consider that on any board, members have different priors about the states of nature for the economy, but they all receive the same signal before deciding, then they will have different posterior probabilities for the states, even if they have many data, if one state has a low probability of occurring, such as an unlikely catastrophic-risk event. Thus, it is not clear what the optimal plan is. Therefore, discretion rather than rules may be the optimal plan in social choice settings.

In time-series from the United States, the relationship between the money to income ratio and the nominal interest rate is a negative and stable one. In Swedish data, there is no such stable relationship. In this paper, we argue that this difference can be explained by the differences in the shock processes that have hit the two countries. Using a dynamic general equilibrium model driven by shock processes estimated to fit the two countries, we find that we can account for the main properties of the data remarkably well.

Guillermo Calvo is one of the most influential economists in the field of international macroeconomics of the past 30 years. He has produced seminal articles in every area of macroeconomics and international economics that he has worked on, including his early classic articles on capacity utilization and time inconsistency, his 1980's works on efficiency wages, price stickiness, and policy credibility, and his recent studies on sudden stops and emerging market crises. Yet, the defining feature of Guillermo Calvo's contribution to our profession is not the depth and wide scope of the economic theories he has developed, but the central emphasis he puts in all his work on the role of economics as a tool for understanding reality and improving the quality of human life.

Guillermo Calvo's passion for the policy implications of economic theory is obvious to anyone who has met him since his days as Senior Advisor of the Research Department of the IMF in the mid-1980's. This feature of his professional interests was much less obvious to those who interacted with him during his early years as an important figure of the rational expectations revolution. It was probably hard to see that behind the highly technical treatment presented in his articles at that time was an author who had his feet soundly set on the ground and focused on understanding how society could benefit from the renaissance of macroeconomic theory that was taking place. Interestingly, Michael Rothschild did figure out the true nature of Guillermo Calvo in those early years. When the University of California at San Diego tried to hire Calvo in the mid-1980's, Rothschild explained to Calvo that he was an excellent fit for San Diego because he was a particular type of theoretician: “Most theoreticians make theory out of theory,” Rothschild noted, but Calvo was different because he made “theory out of reality, taking what is really out there and presenting it in a much wider and complex form than a well-developed but narrow theory.”

The following pages are excerpts from three interview sessions that Guillermo Calvo and I had at his office in the Inter-American Development Bank in the spring of 2003. These interviews provide a clear summary picture of Calvo as the theoretician of reality that Michael Rothschild described. The recollection of the conversation with Rothschild is one of many fascinating memories of Calvo's personal life and professional career that emerged during our meetings. We taped and transcribed the three meetings in Spanish and then Calvo and I together edited that material to produce this much shorter interview in English for Macroeconomic Dynamics.

Externalities are a fundamental aspect of any modern interdependent economy. The fact that agents interact with one another makes it inevitable that their decisions will influence one another directly, in addition to any indirect impact that may occur through the market place. Ever since the earliest stages of the discipline, externalities have been of prime concern to economists, who have long argued that they provide an important motive for (economic) decision making. To cite one prominent example, in The Theory of Moral Sentiments, Adam Smith notes that “Though it is in order to supply the necessities and conveniences of the body that the advantages of external fortune are originally recommended to us, yet we cannot live long in the world without perceiving that the respect of our equals, our credit and rank in the society we live in, depend very much upon the degree in which we possess, or are supposed to possess those advantages. The desire of becoming the proper objects of this respect . . . is perhaps the strongest of all our desires” [Smith (1759, pp. 348–349)]. In modern terminology, Adam Smith is referring to a consumption externality.

When the production function includes dynamic complementarities and a Cobb--Douglas form, dynamic complementarities are an endogenous propagation mechanism of shocks. The proposed model explains several stylized facts of aggregate variables of interest, including (i) hump-shaped impulse response functions, (ii) positively autocorrelated growth rates of aggregate variables, and (iii) correlation coefficients of forecastable movements in aggregate variables.