Essays in Dynamic General Equilibrium Theory

This collection of essays honors David Cass on the 30th anniversary of his joining the faculty of the Department of Economics at the University of Pennsylvania. Prof.

Essays in Dynamic General Equilibrium Theory

In the area of dynamic economics, David Cass’s work has spawned a number of important lines of research, including the study of dynamic general equilibrium theory, the concept of sunspot equilibria, and general equilibrium theory when markets are incomplete. Based on these contributions, this volume contains new developments in the field, written by Cass's students and co-authors.

Essays in Dynamic General Equilibrium

This thesis consists of three chapters studying dynamic economies in general equilibrium.

Essays in Dynamic General Equilibrium

This thesis consists of three chapters studying dynamic economies in general equilibrium. The first chapter considers an economy in business cycles with potentially imperfect financial markets. The second chapter investigates an economy in its balanced growth path with heterogeneous firms. The third chapter analyzes dynamic competitions that these firms are potentially engaged in. The first chapter, "Asset Price and Real Investment Volatility with Heterogeneous Beliefs," sheds light on the role of imperfect financial markets on the economic and financial crisis 2007-2008. This crisis highlights the role of financial markets in allowing economic agents, including prominent banks, to speculate on the future returns of different financial assets, such as mortgage-backed securities. I introduce a dynamic general equilibrium model with aggregate shocks, potentially incomplete markets and heterogeneous agents to investigate this role of financial markets. In addition to their risk aversion and endowments, agents differ in their beliefs about the future aggregate states of the economy. The difference in beliefs induces them to take large bets under frictionless complete financial markets, which enable agents to leverage their future wealth. Consequently, as hypothesized by Friedman (1953), under complete markets, agents with incorrect beliefs will eventually be driven out of the markets. In this case, they also have no influence on asset prices and real investment in the long run. In contrast, I show that under incomplete markets generated by collateral constraints, agents with heterogeneous (potentially incorrect) beliefs survive in the long run and their speculative activities drive up asset price volatility and real investment volatility permanently. I also show that collateral constraints are always binding even if the supply of collateralizable assets endogenously responds to their price. I use this framework to study the effects of different types of regulations and the distribution of endowments on leverage, asset price volatility and investment. Lastly, the analytical tools developed in this framework enable me to prove the existence of the recursive equilibrium in Krusell and Smith (1998) with a finite number of types. This has been an open question in the literature. The second chapter, "Innovation from Incumbents and Entrants," is a joint work with Daron Acemoglu. We propose a simple modification of the basic Schumpeterian endogenous growth models, by allowing incumbents to undertake innovations to improve their products. This model provides a tractable framework for a simultaneous analysis of entry of new firms and the expansion of existing firms, as well as the decomposition of productivity growth between continuing establishments and new entrants. One lesson we learn from this analysis is that, unlike in the basic Schumpeterian models, taxes or entry barriers on potential entrants might increase economic growth. It is the outcome of the greater productivity improvements by incumbents in response to reduced entry, which outweighs the negative effect of the reduction in creative destruction. As the model features entry of new firms and expansion and exit of existing firms, it also generates an equilibrium firm size distribution. We show that the stationary firm size distribution is Pareto with an exponent approximately equal to one (the so-called "Zipf distribution"). The third chapter, "Racing: when should we handicap the advantaged competitor?" studies dynamic competitions, for example R & D competitions used in the second chapters. Two competitors with different abilities engage in a winner-take-all race; should we handicap the advantaged competitor in order to reduce the expected completion time of the race? I show that if the discouragement effect is strong, i.e., both competitors are discouraged from exerting effort when it becomes more certain who will win the race, we should handicap the advantaged. We can handicap him either by reducing his ability or by offering him a lower reward if he wins. Doing so induces higher effort not only from the disadvantaged competitor because of his higher incentive from a higher chance of winning the race but also from the advantaged competitor because of their strategic interactions. Therefore, the expected completion time is strictly shortened. To prove the existence and uniqueness of the equilibria (including symmetric and asymmetric equilibria) that leads to the conclusion, I use a boundary value problem formulation which is novel to the dynamic competition literature. In some cases, I obtain closed-form solutions of the equilibria.

Essays on Political Economy Using Dynamic General Equilibrium Models

This PhD thesis aims to look at four major issues in political economy and macroeconomics, namely, tax evasion, spirit of capitalism, globalisation and production structures involving delayed effects of inputs in dynamic general equilibrium ...

Essays on Political Economy Using Dynamic General Equilibrium Models

This PhD thesis aims to look at four major issues in political economy and macroeconomics, namely, tax evasion, spirit of capitalism, globalisation and production structures involving delayed effects of inputs in dynamic general equilibrium models. These issues are of importance to any economy, but more so to an emerging economy like South Africa. The thesis will not only aim to obtain optimal policy responses in the presence of such distortions (deviations from the traditional Neoclassical world), but will also analyse the effects of these distortions on the growth and welfare of the economy. The thesis aims to have four separate papers based on dynamic general equilibrium (DGE) models: The first paper would aim to explain theoretically why tax evasion might depend on the level of financial development and the inflation rate in the economy. And then, it would try and test whether our proposed theoretical linkage holds in the data using panel data of 150 countries covering the period of 1980-2009. General equilibrium models that include the spirit of capitalism shows a positive relationship between growth and inflation aÌ22́Ơ0́− something unobserved in the data. The literature has tried to reconcile this theoretical and empirical mismatch by introducing human capital, cash-in-advance constraints applying to only specific kind of (non-productive) goods, etc. In the second paper, we, however, aim to show that a simpler way of achieving the negative inflationaÌ22́Ơ0́−growth relationship would be to introduce a banking system in the model subjected to cash reserve requirements. The third paper examines the effect of openness on economic growth, given a human capital accumulation function that captures the marginal benefit of knowledge spillovers in an economy. Two opposing effects are highlighted aÌ22́Ơ0́− one a positive effect from the increase in human capital on growth, the other a negative effect through an increase in seigniorage taxes aÌ22́Ơ0́− that would suggest there is a threshold value of openness, beyond which the impact of opening the economy even more becomes negative for economic growth. The fourth paper would aim to indicate that in the presence of lagged inputs, and especially lagged capital input, in the production structure of an economy, an inflation targeting country might experience aÌ22́Ơ¿3chaoticaÌ22́Ơ℗+ growth behaviour if the inflation target is set too high.

Ph D Thesis

Ph D  Thesis


Essays on Business Cycles and Dynamic Stochastic General Equilibrium Models with Heterogeneous Agents

This dissertation focuses on business cycles and dynamic stochastic general equilibrium models with heterogeneous agents.

Essays on Business Cycles and Dynamic Stochastic General Equilibrium Models with Heterogeneous Agents

This dissertation focuses on business cycles and dynamic stochastic general equilibrium models with heterogeneous agents. Micro-data either for households or for firms are important sources to understand macroeconomic movements. Heterogeneous agent models are useful tools to study the implications of microeconomic aspects of economy on macroeconomy.

Two Essays on Maximum Likelihood Estimations of Dynamic Stochastic General Equilibrium Models

The first essay focuses on a monetary DSGE model of term structure, while the second essay explores and compares three different versions of New Keynesian DSGE models.

Two Essays on Maximum Likelihood Estimations of Dynamic Stochastic General Equilibrium Models

This dissertation consists of two essays on maximum likelihood estimation of Dynamic Stochastic General Equilibrium (DSGE) models. The first essay focuses on a monetary DSGE model of term structure, while the second essay explores and compares three different versions of New Keynesian DSGE models. In Chapter 1, a general background is given for the DSGE models, and their estimation techniques along with a review of the term structure models and New Keynesian models. The first essay, which is a joint work with Hwagyun Kim, empirically evaluates the relationships between money, inflation, output growth, and the interest rates of different maturities using a monetary DSGE model of term structure, featuring inflation targeting behavior, asset market segmentation, and external habit extended for nominal economy. This model can generate liquidity effect, average upward sloping yield curve, and time-varying bond risk premia for bearing inflation and real shocks. By exploiting the term structure equations derived from the model, the deep parameters of the model describing risk preference, inflation targeting behavior, and market segmentation between bond traders and non-traders are estimated. The model is estimated under alternative specifications: latent factors; macroeconomic factors; and both latent and macroeconomic factors. The empirical findings show that all the methods give consistent estimates of the parameters, and conclude that asset market segmentation, inflation targeting, and time-varying risk aversion are significant to account for the term structure dynamics. They also suggest that monetary factors and monetary policy are important to understand both short-run and long-run behaviors of bond prices. In the second essay, three different versions of New Keynesian DSGE models are developed, and their structural parameters are estimated by maximum likelihood estimation. Specifically, the role of velocity of money on the dynamics of real variables is empirically examined by constructing a money in the utility model and two special cases of transactions cost model. Wealth effects, previously ignored in many transactions cost models, are taken into consideration in one of the cases examined here, and comparisons are made between the transactions cost model that includes the wealth effects and the transactions cost model that ignores the wealth effects entirely. The equivalence of money in the utility model and transactions cost model with wealth effects is also quantitatively examined. The results show that there is no evidence of quantitative equivalence between these two models. Although the magnitude of impulse responses are different among the models studied here, all three models give consistent estimates for the structural parameters. The empirical findings from the maximum likelihood estimates of all three models' parameters also suggest that the velocity of money is a very important part of the IS and Phillips curves of all three models developed here, and should be included in IS and Phillips curves when examining the inflation and output dynamics.