We study whether the increased adoption of available automation technologies allows economies to avoid the negative effect of aging on per capita output. We develop a quantitative theory in which firms choose to which extent they automate in response to a declining workforce and rising old-age dependency. An important element in our model is the integration of two capital types: automation capital that acts as a substitute to human labor, and traditional capital that is a complement to labor. Empirically, our model's predictions largely match data regarding automation (robotization) density across OECD countries. Simulating the model, we find that aging-induced automation only partially compensates the negative growth effect of aging in the absence of technical progress in automation technology. One reason is that automated tasks are no perfect substitutes for non-automated tasks. A second reason is that automation raises the interest rate and thus inhibits positive behavioral reactions to aging (later retirement and investment in human capital). Moreover, increased automation generates a falling net labor share of income and rising welfare inequality. We evaluate alternative policy responses to cope with this inequality.

This paper argues that output can respond to public education spending in a delayed and persistent manner through human capital accumulation. We refer to this as a “time-release” response, reflecting that the output response grows as students exposed to increased expenditures sequentially enter the labor market. We first develop and calibrate a stochastic overlapping generations model to formalize the propagation of spending shocks over a long time horizon. We then empirically explore this time-release aspect of shocks to government education expenditures on output using US state-level data for the period 1963–2016 and a panel structural vector autoregression methodology. Consistent with the model, our empirical results show that the dynamic response of output to shocks to government education expenditures is positive, significant, and long-lasting.

Population aging, along with a secular decline in real interest rates, is an empirical regularity observed in developed countries over the last few decades. Under the premise that population aging will deepen in coming years, some studies predict that real interest rates will continue to be depressed further to a level below zero. In this paper, we address this issue and explore how changes in demographic structures have affected and will affect real interest rates, using an overlapping generations model calibrated to Japan’s economy. We find that the demographic changes over the last 50 years reduced the real interest rate. About 270 out of the 640 basis points decline in real interest rates during this period was due to declining labor inputs and higher saving, which themselves stemmed from the lower fertility rate and increased life expectancy. As for the next 50 years, we find that demographic changes alone will not substantially increase or decrease the real interest rate from the current level. These changes reflect the fact that the size of demographic changes in years ahead will be minimal, but that downward pressure arising from the past demographic changes will continue to bite. As Japan is not unique in terms of this broad picture of changes in demographic landscapes in the last and next 50 years, our results suggest that, sooner or later, a demography-induced decline in real interest rates may be contained in other developed countries as well.

This paper reexamines the Serendipity Theorem of Samuelson (1975) from the stability viewpoint, and shows that, for the Cobb–Douglas preference and CES technology, the most-golden golden-rule lifetime state being stable depends on parameter values. In some situations, the Serendipity Theorem fails to hold despite the fact that steady-state welfare is maximized at the population growth rate, since the steady state is unstable. Through numerical simulations, a more general case of CES preference and CES technology is also examined, and we discuss the realistic relevance of our results. We present the policy implication of our result, that is, in some cases, the steady state with the highest utility is unstable, and thus a policy that aims to achieve the social optima by manipulating the population growth rate may lead to worse outcomes.

In this paper, we consider the effects of population aging on a pay-as-you-go financed defined contributions pension scheme. We show that when retirement decisions are endogenous, aging increases the retirement age and the steady-state level of capital. The effect on pension payouts is in general ambiguous, except for the solution of full retirement, when this effect is unambiguously negative.

In this paper, we study the equilibrium dynamics of an overlapping generations model with capital, money, and cash-in-advance constraints. At each period, the economy can experience two different regimes: Either the cash-in-advance constraint is binding and money is a dominated asset, or the constraint is strictly satisfied and money has the same return as capital. When the second regime occurs, we say that the economy experiences a temporary bubble. We show the existence of temporary bubbles, and we prove that cyclical equilibria may exist. In these equilibria, the economy experiences some periods without bubbles and some periods with bubbles. We also show that monetary creation can be used to eliminate temporary bubbles.

Cet article analyse les politiques fiscales à mettre en œuvre afin de lutter contre une externalité de pollution. Nous considérons un modèle à générations imbriquées où seul l'État mène une activité de maintenance de l'environnement, financée par le prélèvement de taxes. L'équilibre concur-rentiel est sous-optimal puisque l'économie est confrontée (i) à un problème de fourniture du bien public qu'est la maintenance, (ii) à une externalité de pollution induite par la consommation, (iii) à l'égoïsme des individus à courte durée de vie. Nous déterminons la structure fiscale telle que l'optimum et l'équilibre concurrentiel coïncident. Nous retrouvons alors la règle de Samuelson, modifiée afin d'intégrer un taux d'actualisation social pertinent, incorporant le taux d'assimilation naturelle de la pollution. Par ailleurs, l'intervention publique ne peut se limiter à neutraliser les flux de polluants : cette activité publique doit prendre en compte, outre une composante de dépollution, une composante optimale d'entretien.

How do taxes affect human capital accumulation? This question has been studied extensively in the context of two model classes: overlapping generations (OLG) and infinite horizon (IH). These embody very different assumptions about the intergenerational transmission of physical and human capital. This paper investigates how such differences in intercohort persistence affect the responsiveness of human capital to taxation. A model is developed that nests OLG and IH models as special cases. The steady-state and transitional effects of tax changes are computed for varying degrees of persistence. The main finding is that stronger intercohort persistence magnifies the impact of taxation on human capital and leads to slower transitional dynamics. As a result, IH models generate systematically larger tax effects than OLG models. For the tax experiments studied here, models with complete persistence generate steady-state tax elasticities at least two times larger and transitional half-lives at least three times longer than do models without persistence.