Rodolfo E. Manuelli

A Convex Model of Equilibrium Growth: Theory and Policy Implications

Our aim in this paper is to exposit a convex model of equilibrium growth. The model has two features that distinguish it from most other work on the subject: first, that the model is convex on the technological side, and second, that fixed factors are explicitly included. Existence and characterization results are provided along with some preliminary analyses of taxation and international trade policies. It is shown that the long-run growth rate in per capita consumption depends, in the natural way, on the parameters describing tastes, technology, and policies. It is demonstrated that in a free-trade equilibrium with taxation, national growth rates of consumption and output need not converge.

Optimal Taxation in Models of Endogenous Growth

We study the problem of optimal taxation in three infinite-horizon, representative-agent endogenous growth models. The first model is a convex model in which physical and human capital are perfectly symmetric. Our second model incorporates elastic labor supply through a Lucas-style technology. Analysis of these two models points out the danger of assuming that government expenditures are exogenous. In our third model, we include government expenditures as a productive input in capital formation, showing that the limiting tax rate on capital is no longer zero. In numerical simulations, we find similar effects on growth and welfare in all three models.

Human Capital and the Wealth of Nations

We reevaluate the role of human capital in determining the wealth of nations. We use standard human capital theory to estimate stocks of human capital and allow the quality of human capital to vary across countries. Our model can explain differences in schooling and earnings profiles and, consequently, estimates of Mincerian rates of return across countries. We find that effective human capital per worker varies substantially across countries. Cross-country differences in Total Factor Productivity (TFP) are significantly smaller than found in previous studies. Our model implies that output per worker is highly responsive to changes in TFP and demographic variables.

Finite Lifetimes and Growth

The recent literature an endogenous growth models has emphasized the effect that the rate of return has an the capital accumulation decisions and, consequently, on the growth rate of the economy. In most cases the basic model is a variant of the representative agent growth model. The key feature of the infinitely lived agent model is that substitution effects dominate, that is, in order to induce individuals to accumulate capital all that is required is a sufficiently high rate of return. In this paper we explore the long run behavior in a model with finite lifetimes -- a version of Diamonds overlapping generations model. Because individuals do not live forever (although the economy does) their level of income as well as the rate of return determine the rate of accumulation. Specifically, we show that for all one sector convex technologies the equilibrium limiting growth rate of the economy is zero. In this setting capital income taxation can have paradoxical effects; it is shown that if the proceeds are used to redistribute income to the young it is possible to have a positive long run growth rate. The effect of the tax rate on the growth rate is not monotonic: for small tax rates the effect is positive, while for sufficiently high rates it is negative. Additionally, income redistribution to the young will normally have positive effects upon the long run growth rate. We then study a two sector growth model and show conditions under which the laissez faire equilibrium displays long run growth. Intuitively, the key property is that the existence of a sector producing investment goods makes it possible that, along a growth path, the relative price of capital decreases sufficiently fast and allows the young to purchase ever increasing quantities of capital. Finally, we show that in an overlawing generations setting, a one sector model can generate growth if the technology displays a nonconvexity, as this is similar to the effect of a decrease in the price of capital: it prevents the ratio of the value of capital am the level of wealth of the young from exceeding one.

The sources of growth

In this paper, we survey the principal theoretical models of endogenous growth and explore their common components through analyzing a series of planning problems. Our aim is to provide the reader with a consistent approach to the emerging literature on growth as an introduction to the field.

Chapter 1 Neoclassical Models of Endogenous Growth: The Effects of Fiscal Policy, Innovation and Fluctuations

Despite its role as the centerpiece of modern growth theory, the Solow model is decidedly silent on some of its basic questions: Why is average growth in per capita income so much higher now than it was 200 years ago? Why is per capita income so much higher in the member countries of the OECD than in the less developed countries (LDC) of the world? In this chapter we review the recent literature on endogenous growth. We concentrate on convex models and we restrict attention to the case in which markets are competitive.After a brief review of the basic mechanisms that produces growth, we concentrate on three topics: the impact of fiscal policies on growth, the role of innovation and the relationship between uncertainty and growth.

A model of price swings in the housing market

In this paper we use a standard neoclassical model supplemented by some frictions to understand large price swings in the housing market. We construct a two good general equilibrium model in which housing is a composite good produced using structures and land. We revisit the connection between changes in interest rates, credit conditions as measured by maximum loan-to-value ratios and expectations in influencing housing prices in a setting in which the stock of housing can be used as collateral for borrowing and credit markets are segmented. We find that changes in interest rates and credit conditions can generate significant price swings. Under rational expectations (perfect foresight) our model is able to explain 50% of the recent movements in U.S. house prices. When we allow shocks to expectations, the model’s ability to match the evidence increases significantly. Contrary to conventional wisdom, we show that standard asset pricing formulas seem to correctly describe the behavior of house prices if the appropriate pricing kernel is used.

Volatile Policy and Private Information: The Case of Monetary Shocks

In this paper we study how volatility in monetary policy affects economic performance in the presence of endogenously chosen information structures. To isolate the effects produced by the interaction of uncertainty in monetary policy and (possibly) asymmetric information, we consider a model in which in the absence of either one of these features the equilibrium would be efficient. The equilibria that we find, with volatility and asymmetry of information, are inefficient for two reasons: first, in some cases, economic agents fail to trade, even though it is always efficient to do so; second, to capture the rents associated with being informed, agents spend resources acquiring socially useless information. Thus, in addition to the more standard effects of volatile inflation, our model calls attention to two types of costs associated with monetary uncertainty: the cost of not trading, and the cost of allocating resources to wasteful activities. The model implies that if monetary policy is not volatile all agents are symmetrically informed and hence, the outcome is efficient. Alternatively, making policy transparent, i.e guaranteeing that all agents share the same information, serves the same purpose.

Endogenous growth theory: An introduction☆

Abstract This essay introduces a collection of articles that deal with a series of topics in the area of new or endogenous growth theory. The introduction provides an overview of the collection and summaries of individual articles.

Lifetime Labor Supply and Human Capital Investment

We develop a model of retirement and human capital investment to study the effects of tax and retirement policies. Workers choose the supply of raw labor (career length) and also the human capital embodied in their labor. Our model explains a significant fraction of the US-Europe difference in schooling and retirement. The model predicts that reforms of the European retirement policies modeled after the US can deliver 15-35 percent gains in per-worker output in the long run. Increased human capital investment in and out of school accounts for most of the gains, with relatively small changes in career length. JEL classification: E24; J24