Cagri Saglam

Technology adoption under embodiment : A two-stage optimal control approach

We use two stage optimal control techniques to solve some adoption problems under embodied technical change. We first solve a benchmark problem without learning behavior. At the date of switching, the consumption level is shown to drop, as the relative price of capital goes down (obsolescence). In such a case, the economy sticks to the initial technology, or immediately switches to a new technology with a higher level of embodiment, depending on how the obsolescence costs compare to the induced growth advantage. In a second step, we introduce learning. The learning curve involves fixed costs and incentives to wait as well. Adoption is shown to depend on the growth advantage of switching net of obsolescence and learning fixed costs. The economy will switch if and only if this indicator is positive. If it is big enough to compensate the option of waiting, then the economy switches immediately. Otherwise, the economy waits.

The Development problem under embodiment

This paper studies technology adoption in an optimal growth model with embodied technical change. The economy consists of the final good sector, the capital sector, and the technology sector which role is the imitation of exogenous innovations. Scarce labor resources are allocated to the technology and final good sectors. The final good is allocated to consumption and to the capital sector. The authors analytically characterize the long run optimal allocations. Using a calibrated version of the model, they find that an acceleration in the rate of embodied technical change should not be responded by an immediate and strong adoption effort. Instead, adoption labor should decrease in the short run, and the optimal technological gap is shown to increase either in the short or in the long run. The state of the institutions and policies around the technology sector is key in the design of the optimal adoption timing.

Capital Maintenance versus Technology Adoption under Embodied Technical Progress

We study an optimal growth model with one-hoss-shay vintage capital, where labor resources can be allocated freely either to production, technology adoption or capital maintenance. Technological progress is partly embodied. Adoption labor increases the level of embodied technical progress. First, we are able to disentangle the amplification-propagation role of maintenance in business fluctuations: in the short run, the response of the model to transitory shocks on total factor productivity in the final good sector are definitely much sharper compared to the counterpart model without maintenance but with the same average depreciation rate. Moreover, the one-hoss shay technology is shown to reinforce this amplification-propagation mechanism. We also find that accelerations in embodied technical progress should be responded by a gradual adoption effort, and capital maintenance should be the preferred instrument in the short run.

STRATEGIC INTERACTION AND CATCHING UP

In this study, we prove that the strategic interaction among agents differing in initial wealth levels leads the poor to be able to catch up with the rich, which is not the case for the standard Ramsey model where the initial wealth differences perpetuate. Extending the analysis to account for relative wealth concern and the adjustment cost of consumption, the strategic interaction among agents is shown to affect not only the distribution of wealth in the long run but also the transitional dynamics substantially. In particular, we show that structurally very simple frameworks may lead to limit cycles thanks to the strategic interaction among agents in the economy.

Saddle-node bifurcations in an optimal growth model with preferences for wealth habit

Abstract This paper studies the dynamic implications of preferences for wealth habit in a one-sector optimal growth model. We show that the dynamics may encounter saddle-node bifurcations with respect to the parameters of the preferences: the relative weight of wealth in utility and the degree of wealth habit. We analytically provide the monotone comparative statics and the continuity of the critical capital stock with respect to the discount factor, the relative weight of wealth in utility and the degree of wealth habit.

Capital Maintenance as a Key Development Tool

We construct optimal growth models where labor resources can be allocated either to production, technology adoption or capital maintenance. We first characterize the balanced growth paths of a benchmark model without maintenance. Then we introduce maintenance activity via the depreciation rate of capital. We characterize the optimal allocation of labor across the three activities. Although maintenance deepens the technological gap by diverting labor resources from adoption, we show that it generally increases the long run output level. Moreover, we find that equilibrium maintenance and adoption efforts respond in opposite directions to policy or technology shocks. Finally, we find that the long-term output response to policy shocks is slightly higher in the presence of maintenance.

Investment on human capital in a dynamic contest model

Abstract Although most contest games are modeled in such a way that the outcome depends only on the efforts exerted by the contestants, what is arguably more important is the contestants’ effective efforts which may be influenced also by their ability, human capital, strength, etc. In this paper, we investigate an extensive model including such an effectiveness parameter and analyze the optimal investment behavior in a dynamic conflict framework. At each period, two contestants compete for a common prize by choosing contest efforts and investment levels. Each contestant’s investment accumulates as his/her human capital which depreciates through time. Who wins the component contest at a particular period is determined by the contestants’ effective efforts, defined as increasing functions of their efforts and human capitals. Following the analysis of subgame perfect Nash equilibrium in a two-period model and of open-loop equilibrium in an infinite-horizon model, we provide intuitive comparative static results.

Robust Comparative Statics for Non-monotone Shocks in Large Aggregative Games

A policy change that involves redistribution of income or wealth is typically controversial, affecting some people positively but others negatively. In this paper we extend the robust comparative statics result on large aggregative games established by Acemoglu and Jensen (2010, 49th IEEE Conference on Decision and Control, 3133-3139) to possibly controversial policy changes. In particular, we show that both the smallest and the largest equilibrium values of an aggregate variable increase in response to a policy change to which individuals reactions may be mixed but the overall aggregate response is positive. We provide sufficient conditions for such a policy change in terms of distributional changes in parameters.

A Territorial Conflict: Trade-offs and Strategies

We study a war scenario in which the winner occupies the loser’s territory. Attacking a territory increases the chance of winning, but also causes harm, which in turn decreases the territory’s value (i.e. the reward of winning). This paper highlights the effects of this trade-off on the equilibrium strategies of the warring states in a contest game with endogenous rewards. Providing both static and dynamic models, our analysis captures insights regarding strategic behavior in asymmetric contests with such conflict.