In this paper I study the impact of increasing longevity on pay-as-you-go pension systems. First, I show that increasing longevity increases the internal rate of return. The size of the effect differs for different policy regimes. It is higher for the case where the retirement age is increased to keep the system in balance than for the case where the necessary adjustment is achieved by reducing pension benefits. Second, I study optimally chosen retirement decisions and I show that the socially optimal policy involves a shorter working life than the private optimum. The social optimum can be implemented by the use of a PAYG system that combines an actuarial and a flat pension.

To explain the high and persistent unemployment rate in the United States during and after the Great Recession, this effort develops and estimates a dynamic stochastic general equilibrium model with search and matching frictions and shocks to unemployment benefits and matching efficiency. It finds that unemployment benefits play an important role in the cyclical movement of unemployment through their effects on labor demand, a channel overlooked in previous studies. From the second half of 2008 to 2011, extended unemployment benefits may have increased the overall unemployment rate by one percentage point. In contrast, matching efficiency changes had less effect on the cyclical movement of unemployment for the same period, but significantly slowed down the recovery after 2012.

This paper proposes an alternative measure for the slack of the aggregate labor market. The natural rate of hours holds valuable information about the state of the labor market that is not reflected by conventional measures, such as the equilibrium rate of unemployment, because it takes the intensive margin into account and is robust to variations in labor force participation. We set up and estimate a multivariate unobserved-components model using information on GDP, inflation, and hours worked, and apply it to the United States and Germany. The estimated hours gap outperforms conventional unemployment gap measures in a Taylor rule by formal model comparison.

In this study I bring together two different literatures: the hierarchical education literature and the skill-biased growth literature. In an overlapping-generations model I introduce capital–skill complementarity into a hierarchical education system. I obtain results that differ qualitatively from previous studies, among which are the following: (i) At earlier stages of development, basically educated labor contributes to growth more than highly educated labor. The opposite occurs at later stages. (ii) Even when all individuals acquire higher education, a growth-enhancing policy subsidizes higher education. (iii) In a growth-enhancing policy, the share of public resources allocated to basic education declines as the economy grows. (iv) The enrollment rate evolves in an S-shaped pattern, as occurred in several OECD countries.

Using postwar U.S. data, I study the implied interest rates in a simple long-run risk (LRR) model. Empirical estimates show that, as in standard consumption-based models with power utility preferences, the movements of the implied risk-free rate are entirely determined by the variations of expected consumption growth. This leads to a negative relationship between LRR Euler equation rates and money market rates. Nevertheless, when the low-frequency movements of consumption growth are accounted for, the long-run component of consumption growth is a key element to partially capture the countercyclical variations of the money market rates.

We construct an endogenous growth model that includes productive public capital and government debt. We assume that the government debt-to-GDP ratio is gradually adjusted to a target level, reflecting the permanent commitment rules in the Stability and Growth Pact or the Maastricht Treaty in the European Union (i.e., the well-known 60% rule). These rules affect government borrowing and public investment. Here, we examine the welfare implications of the permanent commitment rules. We find that fiscal consolidation based on the rules improves social welfare. Moreover, the improvement in welfare accelerates as fiscal consolidation progresses more rapidly. Last, we also discuss and derive the optimal long-run debt-to-GDP ratio.

I develop and calibrate an equilibrium search model with endogenous savings and search intensity. The wage is endogenized using Nash bargaining and the number of vacancies is tied down by a free entry condition. This allows me to conduct a counterfactual analysis of the optimal unemployment insurance (UI) level. The provision of UI is motivated by the worker's inability to perfectly insure against income shocks, but at the same time UI introduces distortions into workers' search intensity decisions and firm vacancy creation. I find that equilibrium effects are important. When the UI level is raised 25%, they constitute around one-third of the increase in total unemployment. However, even with limited savings by workers, optimal UI is close to zero. It is further shown that ignoring the possibility of self-insurance greatly affects the optimal UI level.

In this paper, a dynamic general equilibrium model with infinitely lived entrepreneurs and financiers is developed to investigate a possible mechanism that explains business cycles and financial crises. The highest growth rate is achievable only if financiers coexist with entrepreneurs, given a certain extent of financial market imperfections. However, if financiers coexist with entrepreneurs, the economy is highly likely to face a financial crisis at certain parameter values. These two-sided implications of the coexistence of entrepreneurs and financiers explain why both instability and high growth are frequently observed in modern economies. Furthermore, our model can obtain countercyclical movements in total factor productivity growth that cannot be explained by the standard real business cycle theory but were observed in the Great Recession of 2007–2008.

A few years ago we sat down with Neil Wallace and had two lengthy, free-ranging conversations about his career and, generally speaking, his views on economics. What follows is a distillation of these conversations.

We analyze the implications of openness and growth for determinacy and learnability of rational expectations equilibria in a two-country New Keynesian model with alternative monetary policy rules. Under the contemporaneous data rule, the conditions for determinacy and learnability become more stringent as a result of openness but less stringent as a result of growth, so that growth weakens the effect of openness. Under the expectations-based rule, the conditions for determinacy and learnability also become more stringent as a result of openness, whereas as a result of trend growth the conditions for determinacy also become more stringent (thus reinforcing the effect of openness) but those for learnability become less stringent (thus weakening the effect of openness). As in related studies, the elasticity of intertemporal substitution is key to our result, but within a framework that is consistent with long-run labor supply and balanced growth facts.

Although a realistic characterization of the production function is critical to macroeconomic analysis, estimating the function's characteristics is hampered by both data limitations and methodological difficulties. In this paper, I develop a new empirical strategy for estimating the CES production function with biased technical change. The proposed method extends the control function approach to the CES specification to address endogeneity concerns and is able to retrieve sector-specific and time-varying estimates of technical change. Using data from U.S. manufacturing industries, I find evidence that (i) the production technology exhibits nonincreasing returns to scale, (ii) the elasticity of substitution between capital and labor is below unity, and (iii) technical change is generally labor-augmenting along the balanced growth path.

Many algorithms that provide approximate solutions for dynamic stochastic general equilibrium (DSGE) models employ the QZ factorization because it allows a flexible formulation of the model and exempts the researcher from identifying equations that give raise to infinite eigenvalues. We show, by means of an example, that the policy functions obtained by this approach may differ from both the solution of a properly reduced system and the solution obtained from solving the system of nonlinear equations that arises from applying the implicit function theorem to the model's equilibrium conditions. As a consequence, simulation results may depend on the specific algorithm used and on the numerical values of parameters that are theoretically irrelevant. The sources of this inaccuracy are ill-conditioned matrices as they emerge, e.g., in models with strong habits. Researchers should be aware of those strange effects, and we propose several ways to handle them.

In previous papers [Spear and Young (2014, 2015)], we surveyed the origins, evolution, and dissemination of optimal growth, two-sector and turnpike models up to the early 1970s. Regarding subsequent developments in growth theory, a number of prominent observers, such as Fischer (1988), Stern (1991), and McCallum (1996), maintained that after significant progress in the 1950s and 1960s, economic growth theory “received relatively little attention for almost two decades” [Fischer (1988, p. 329)], and that “by the late 1960s early 1970s, research on the theory of growth more or less stopped” [Stern (1991, p. 259)]. Stern went on to say “the latter half of the 1980s saw a rekindling of growth theory, particularly in the work of Romer . . . and Lucas” (1991, p. 259), that is to say, in the form of “endogenous growth” models. McCallum, for his part, wrote (1996, p. 41), “After a long period of quiescence, growth economics has in the last decade (1986–1995) become an extremely active area of research.” Moreover, Brock and Mirman's (1972b) paper was the sole “extension” of Ramsey–Cass–Koopmans to a “stochastic environment” mentioned by McCallum (1996, 49).

We try to understand the nature of Japan's sovereign credit risk by examining the interaction between Japan's sovereign credit default swap (CDS) spreads and its financial indicators of macroeconomic fundamentals. We consider potential contagion from the global financial market and allow for reverse causality between CDS spreads and macroeconomic fundamentals. We find strong evidence of contagion from global stock markets to Japan's credit market when Lehman Brothers collapsed, whereas the European sovereign debt crisis only had temporary effects. We also show that several credit events, such as the 2011 Tohoku earthquake and rating cuts by rating agencies, significantly raised volatility in Japan's sovereign CDS market.

We investigate the role of nonseparable preferences in the occurrence of macroeconomic instability under a balanced-budget rule where government spending is financed by a tax on labor income. Considering a one-sector neoclassical growth model with a large class of nonseparable utility functions, we find that expectations-driven fluctuations occur easily when consumption and labor are Edgeworth substitutes or weak Edgeworth complements. Under these assumptions, an intermediate range of tax rates and a sufficiently low elasticity of intertemporal substitution in consumption lead to instability.

Should foreign aid be tied or untied? We study this question in the context of a dynamic growth model in which agents can accumulate human capital through education. We compare the growth and welfare implications of three polar scenarios in which foreign aid is either (i) completely untied, (ii) tied to public investment in infrastructure, or (iii) tied to public spending on education. Our results indicate that tying aid to education is more beneficial from a long-run welfare perspective than the two alternative scenarios. We also compute the optimal allocation of foreign aid and find that the largest fraction of aid flows ought to be tied to public spending on education. Finally, we study the transitional dynamics of the recipient economy following an aid inflow and find that aid programs that are tied (entirely or partially) to public spending on education generally entail some welfare losses in the short run.

We examine U.S. monetary policies from 1973 to 2014 with the Taylor rule as a benchmark by utilizing a k-state Markov regime-switching model in which the number and the periods of the regimes are endogenously determined. The model relates the federal funds rate to real time output gaps and inflation forecast. It endogenously identifies the periods of Taylor rule regime and discretionary regimes, consistent with the U.S. experience. The Taylor rule regime also coincides with periods of lower variability in inflation and in real GDP growth.

The rationality test is based on regressing the actual series of variable in period t on its forecast formed in period t − 1. The nonrejection of the rationality hypothesis requires expectations' unbiasedness and efficiency. We show that in a model with t − 1 dating, where expectations strongly and positively affect the economy, the rationality test suffers from low power. It provides a high probability of nonrejection of the rationality hypothesis against numerous alternatives for expectations formation. This result is attained because the realization of the economy is driven by the public's expectations, irrespective of how well they are formed, via the structural relationship between them. The parameters in this test are predetermined by the parameters of the structural model, supporting expectations' unbiasedness under reasonable assumptions. Thus, successfully passing the rationality test could be misleading in terms of interpretation of the quality of the expectations and could lead to questionable accuracy of many applications.

We study production functions with capital and labor as arguments that exhibit positive, yet diminishing marginal products and constant returns to scale. We show that such functions satisfy the Inada conditions if (i) both inputs are essential and (ii) an unbounded quantity of either input leads to unbounded output. This allows for an alternative characterization of the neoclassical production function that altogether dispenses with the Inada conditions. Although this proposition generalizes to the case of n > 2 factors of production, its converse does not hold: 2n Inada conditions do not imply that each factor is essential.