A classic result in dynamic public economics states that there is no welfare rationale for pay-as-you-go (PAYG) pensions in a dynamically efficient overlapping-generations economy with exogenous labor supply. Parenthetically, a welfare justification for PAYG pensions exists if the economy is dynamically inefficient. Under the sufficient condition that the old be no less risk-averse than the young, both these results extend to an economy with endogenous labor supply.

We study adaptive learning in economic environments subject to recurring structural change. Stochastically evolving institutional and policymaking features can be described by regime-switching models with parameters that evolve according to finite state Markov processes. We demonstrate that in nonlinear models of this form, the presence of sunspot equilibria implies two natural schemes for learning the conditional means of endogenous variables: under mean value learning, agents condition on a sunspot variable that captures the self-fulfilling serial correlation in the equilibrium, whereas under vector autoregression learning (VAR learning), the self-fulfilling serial correlation must be learned. We show that an intuitive condition ensures convergence to a regime-switching rational expectations equilibrium. However, the stability of sunspot equilibria, when they exist, depends on whether agents adopt mean value or VAR learning: coordinating on sunspot equilibria via a VAR learning rule is not possible. To illustrate these phenomena, we develop results for an overlapping-generations model and a New Keynesian model.

In Mankiw, Romer, and Weil's augmented Solow model [Quarterly Journal of Economics 107 (2) 407–437 (1992)], the marginal product of human capital accrues to three factors of production: directly to human capital, and as an external effect to physical capital and labor. This paper estimates national stocks of human capital in 1990 created from prior investment in schooling and shows that for 36 countries the (macro) marginal product of human capital accruing to workers in 1990 is consistent with estimates of the (micro) marginal return on investment in schooling in workers' earnings studies. This reconciliation provides empirical evidence for the augmented Solow model.

We examine a general equilibrium model with collateral constraints and increasing returns to scale in production. The utility function is nonseparable, with no income effect on the consumer's choice of leisure. Unlike this model without a collateral constraint, we find that indeterminacy of equilibria is possible. Hence, business cycles can be driven by self-fulfilling expectations. This is the case for more realistic parameterizations than in previous, similar models without these features.

This paper develops a two-sector small open economy model to analyze the effects of the currency denomination of debt on default risk and interest rates in emerging market economies. Default risk is determined endogenously and depends on the incentives for repayment. The economy can borrow using tradable-denominated nonindexed bonds or bonds whose return is indexed to the domestic price index, which are used as proxies for foreign currency and domestic currency debt, respectively. The model predicts that foreign currency debt leads to lower default risk for high output levels and domestic currency debt reduces the default risk for low output levels. Although the effect of debt denomination on default risk changes with the output level, the default rate of the economy and average interest rates decline as domestic currency borrowing increases. In addition, domestic currency borrowing is found to reduce the countercyclicality of interest rates and the trade balance.

This paper explores the consequences of tax enforcement policies for monetary policy. Agents may evade taxes by working in the informal sector, but they are detected with positive probability. Workers are rewarded with government benefits that are proportional to formal (taxed) work. When enforcement is imperfect and collecting taxes is costly, the optimal inflation rate is positive and inflation becomes a second-best tax. Deviations from the Friedman rule are optimal and depend on the tax enforcement policies. Using U.S. data, we compute the quantitative effect of different tax structures on inflation and interest rate. We show that different tax enforcement and government spending (benefits) policies induce different optimal outcomes for inflation and interest rates.

This paper explores the dynamics of semiendogenous versus fully endogenous growth models in “lab equipment” specifications of the models with expanding sectors. Capital is allowed to accumulate and is used, together with other inputs, to produce new knowledge. The stability of the steady state path is found to be determined by the inequality and/or knife-edge restrictions needed to produce steady state growth. This paper takes the ratio of the shadow price of capital to knowledge and the level of consumption as jump variables. Semiendogenous growth models lead to a 4 × 4 dynamic system where the sign of the coefficient matrix of the log linearized dynamic system is indefinite, leading to a potential for both stable and unstable equilibria. The knife-edge restrictions needed to generate policy influences on growth are shown to be restrictions that reduce the system to 3 × 3 with a positive definite coefficient matrix, thereby guaranteeing a globally stable equilibrium. Implications for empirical testing are addressed.

We develop an overlapping-generations model of growth and the environment in relation to public policy on education. Beyond the traditional mechanisms through which knowledge, growth, and the environment interplay, we stress the role played by education in environmental awareness. Assuming first that environmental awareness is constant, we show the existence of a balanced-growth path (BGP) along which environmental quality increases continually. Then, if education enhances environmental awareness, the equilibrium properties are modified: the economy can reach a steady state or converge to an asymptotic BGP. Therefore, education does not necessarily promote sustained and sustainable growth.

This note evaluates whether a New Open Economy model can reproduce qualitatively the observed fluctuations of the tradeable and nontradeable sectors of the U.S. economy. The answer is positive: both in the model and in the data, the standard deviations of tradeable inflation, output, and employment are significantly higher than the standard deviations of the corresponding nontradeable sector variables. The key role in generating this result is played by the greater responsiveness of tradeable sector variables to monetary shocks.

The transcript of a panel discussion marking the 50th anniversary of John Muth's “Rational Expectations and the Theory of Price Movements” (Econometrica 1961). The panel consisted of Michael Lovell, Robert Lucas, Dale Mortensen, Robert Shiller, and Neil Wallace. The discussion was moderated by Kevin Hoover and Warren Young. The panel touched on a wide variety of issues related to the rational-expectations hypothesis, including its history, starting with Muth's work at Carnegie Tech; its methodological role; applications to policy; its relationship to behavioral economics; its role in the recent financial crisis; and its likely future.

The panel discussion was held in a session sponsored by the History of Economics Society at the Allied Social Sciences Association (ASSA) meetings in the Capitol 1 Room of the Hyatt Regency Hotel in Denver, Colorado.