Omar Licandro

Vintage Human Capital, Demographic Trends and Endogenous Growth

We study how economic growth is affected by demographics in an overlapping generations model with a realistic survival law. Individuals optimally chose the dates at which they leave school to enter the labor market and at which they retire. Endogenous growth arises thanks to the accumulation of generation-specific human capital. Favorable shifts in the survival probabilities always induce longer schooling and later retirement but have an ambiguous effect on growth. The relationship between the growth of population and per-capita growth is hump-shaped. Increases in longevity can be responsible for a switch from a no-growth regime to a sustained growth regime and for a positive relationship between fertility and growth to vanish.

Life Expectancy and Endogenous Growth

We consider an overlapping generations model with uncertain lifetime and endogenous growth. Individuals have to choose the length of time devoted to schooling before starting to work. We show that it depends positively on life expectancy but that the positive effect of a longer life on growth could be offset by a decrease in the participation rate. Dynamics are characterized by a delay differential equation and human capital converges with oscillations to a balanced growth path.

Creative destruction, investment volatility, and the average age of capital

In this article, a new numerical procedure is used to compute the equilibrium of a vintage capital growth model with nonlinear utility, where the scrapping time is nonconstant. We show that equilibrium investment and output converge nonmonotonically to the balanced growth path due to replacement echoes. We find that the average age of capital is inversely related to output, which is consistent with recent micro evidence reinforcing the importance of the embodied question. We also find that an unanticipated permanent increase in the rate of embodied technological progress causes labor productivity to slowdown in the short run.

'The Child is Father of the Man:' Implications for the Demographic Transition

face a second trade-off in allocating their time between increasing their own human capital and rearing children. The model displays different regimes. In a Malthusian regime with no education fertility increases with adult life expectancy. In the modern growth regime, life expectancy and fertility move in opposite directions. The dynamics display the key features of the demographic transition, including the hump in both population growth and fertility, and replicate the observed rise in educational attainment, adult life expectancy and economic growth. Consistent with the empirical evidence, a distinctive implication of our theory is that improvements in childhood development precede the increase in education.

Differential-difference equations in economics: On the numerical solution of vintage capital growth models

In this papel, we examine techniques for the analytical and numerical solution of statedependent differential-difference equations. Such equations occur in the continuous time modelling of vintage capital growth models, which form a particularly important class of models in modern economic growth theory. The theoretical treatment of non-statedependent differential-difference equations in economics has already been discussed by Benhabib and Rustichini (1991). In general, though, the state-dependence of a model prevents its analytical solution in all but the simplest of cases. We review a numerical method for solving state-dependent models, using sorne simple examples to illustrate our discussion. In addition, we analyse the Solow vintage capital growth model. We conclude by mentioning a crucial unresolved issue related to this topic.

Embodied technological change learning-by-doing and the productivity slowdown

The productivity slowdown faced by the US economy since the first oil shock has been associated with a rise in the decline rate of the relative price of equipment and a reduction in the rate of disembodied technical change. We build up a growth model in which learning-by-doing is the engine of both embodied and disembodied technological progress. A change in the relative efficiency of learning-by-doing from the consumption to the investment sector is shown to imply a technological reassignment consistent with the above mentioned evidence. This result derives from the interaction between the obsolescence costs inherent to embodiment and the learning-by-doing engine.

MODELLING VINTAGE STRUCTURES WITH DDEs: PRINCIPLES AND APPLICATIONS*

A comprehensive study of the linkages between demographic and economic variables should not only account for vintage specificity but also incorporate the relevant economic and demographic decisions in a complete optimal control set-up. In this paper, a methodological set-up allowing to reach these objectives is described. In this framework, time is continuous but agents take discrete timing decisions. The mixture of continuous and discrete time yields differential-difference equations (DDEs). This paper shows clearly that the approach allows for a relatively complete and rigorous analytical exploration in some special cases (mainly linear or quasi linear models), and for an easy computational appraisal in the general case.

Capital Utilization, Maintenance Costs and the Business Cycle

In this paper we analyze the role played by capacity utilization and maintenance costs in the propagation of aggregate fluctuations. To this purpose we use an extension of the general equilibrium stochastic growth model that incorporates a depreciation technology depending both upon capital utilization (depreciation in use assumption) and maintenance costs. In addition, we argue that the maintenance activity must be countercyclical, because it is cheaper for the firm to repair and maintain machines when they are stopped than when machines are being employed. We show that the propagation mechanism associated to our technology assumption is quantitatively important: the countercyclicality of maintenance costs contributes significantly to magnify and propagate aggregate fluctuations.

Trade Liberalization, Competition and Growth

Increasing evidence supports that international trade enhances innovation and productivity growth through an increase in competition. This paper develops a two-country endogenous growth model, with firm specific R&D and a continuum of oligopolistic sectors under Cournot competition to provide a theoretical support to this claim. Since countries are assumed to produce the same set of varieties, trade openness makes markets more competitive, reducing prices and increasing quantities. Since firms undertake cost reducing innovations, the increase in production pushes firms to innovate more. Compared to other oligopolistic competition models, we find a larger pro-competitive effect of trade on innovation under this framework, and this effect is increasing the larger the elasticity of substitution between products.

Numerical solution by iterative methods of a class of vintage capital models

We build up an iterative numerical procedure in order to solve vintage capital growth models with nonlinear utility functions and Leontieff technologies, a class of models intensively used in the literature since the early 1990s. The numerical procedure is of the relaxation type and uses a step-by-step maximization scheme for updating, The procedure is close to the cyclic coordinate descent algorithm as described in the computational mathematics literature. We explain why and how our numerical scheme is suitable to handle the considered class of models