Robert M. Solow

Bio: Robert M. Solow is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Unemployment & Medicine. The author has an hindex of 77, co-authored 264 publications receiving 57825 citations. Previous affiliations of Robert M. Solow include Princeton University & New York University.

Modigliani e Keynes

Abstract: Il primo articolo pubblicato di Franco Modigliani e divenuto uno dei testi base della moderna economia keynesiana. In esso ha formalizzato il modello (o almeno un modello) implicito nella Teoria Generale . Modigliani sosteneva che le caratteristiche conclusioni keynesiane poggiano fondamentalmente sulla (realistica) rigidita dei salari nominali. In particolare, ha mostrato che se i salari e i prezzi fossero flessibili, la teoria della preferenza di liquidita della moneta non potrebbe generare persistente disoccupazione involontaria, ma se i salari fossero rigidi, anche la teoria della quantita della moneta potrebbe farlo. Sessant’anni piu tardi Modigliani e tornato a esporre il “vangelo keynesiano” e ha proposto essenzialmente la medesima interpretazione. Questo articolo riconsidera e discute questo approccio alla macroeconomia, con alcuni riferimenti alle sue implicazioni per la politica economica. The first article published by Franco Modigliani has become one of the basic texts of the modern Keynesian economics. It formalized the model (or at least one model) implicit in the General Theory. Modigliani argued that the characteristics Keynesian conclusions are based primarily on the (realistic) rigidity of nominal wages. In particular, it showed that if wages and prices were flexible, the theory of liquidity preference of money could not generate persistent involuntary unemployment, but if wages were rigid, the theory of the amount of money could do it. Sixty years later Modigliani returned to expose the "Keynesian gospel" and proposed essentially the same interpretation. This article reconsiders and discusses this approach to macroeconomics, with some reference to its implications for economic policy. JEL Codes: B22, E12 Keywords: Franco Modigliani, verifiche empiriche, ciclo vitale, Keynes, disoccupazione, teoria della spesa

A Contribution to the Empirics of Economic Growth

Abstract: This paper examines whether the Solow growth model is consistent with the international variation in the standard of living. It shows that an augmented Solow model that includes accumulation of human as well as physical capital provides an excellent description of the cross-country data. The paper also examines the implications of the Solow model for convergence in standards of living, that is, for whether poor countries tend to grow faster than rich countries. The evidence indicates that, holding population growth and capital accumulation constant, countries converge at about the rate the augmented Solow model predicts. This paper takes Robert Solow seriously. In his classic 1956 article Solow proposed that we begin the study of economic growth by assuming a standard neoclassical production function with decreasing returns to capital. Taking the rates of saving and population growth as exogenous, he showed that these two vari- ables determine the steady-state level of income per capita. Be- cause saving and population growth rates vary across countries, different countries reach different steady states. Solow's model gives simple testable predictions about how these variables influ- ence the steady-state level of income. The higher the rate of saving, the richer the country. The higher the rate of population growth, the poorer the country. This paper argues that the predictions of the Solow model are, to a first approximation, consistent with the evidence. Examining recently available data for a large set of countries, we find that saving and population growth affect income in the directions that Solow predicted. Moreover, more than half of the cross-country variation in income per capita can be explained by these two variables alone. Yet all is not right for the Solow model. Although the model correctly predicts the directions of the effects of saving and

Endogenous Technological Change

Abstract: Growth in this model is driven by technological change that arises from intentional investment decisions made by profit-maximizing agents. The distinguishing feature of the technology as an input is that it is neither a conventional good nor a public good; it is a nonrival, partially excludable good. Because of the nonconvexity introduced by a nonrival good, price-taking competition cannot be supported. Instead, the equilibrium is one with monopolistic competition. The main conclusions are that the stock of human capital determines the rate of growth, that too little human capital is devoted to research in equilibrium, that integration into world markets will increase growth rates, and that having a large population is not sufficient to generate growth.

Macroeconomics and reality

Abstract: Existing strategies for econometric analysis related to macroeconomics are subject to a number of serious objections, some recently formulated, some old. These objections are summarized in this paper, and it is argued that taken together they make it unlikely that macroeconomic models are in fact over identified, as the existing statistical theory usually assumes. The implications of this conclusion are explored, and an example of econometric work in a non-standard style, taking account of the objections to the standard style, is presented. THE STUDY OF THE BUSINESS cycle, fluctuations in aggregate measures of economic activity and prices over periods from one to ten years or so, constitutes or motivates a large part of what we call macroeconomics. Most economists would agree that there are many macroeconomic variables whose cyclical fluctuations are of interest, and would agree further that fluctuations in these series are interrelated. It would seem to follow almost tautologically that statistical models involving large numbers of macroeconomic variables ought to be the arena within which macroeconomic theories confront reality and thereby each other. Instead, though large-scale statistical macroeconomic models exist and are by some criteria successful, a deep vein of skepticism about the value of these models runs through that part of the economics profession not actively engaged in constructing or using them. It is still rare for empirical research in macroeconomics to be planned and executed within the framework of one of the large models. In this lecture I intend to discuss some aspects of this situation, attempting both to offer some explanations and to suggest some means for improvement. I will argue that the style in which their builders construct claims for a connection between these models and reality-the style in which "identification" is achieved for these models-is inappropriate, to the point at which claims for identification in these models cannot be taken seriously. This is a venerable assertion; and there are some good old reasons for believing it;2 but there are also some reasons which have been more recently put forth. After developing the conclusion that the identification claimed for existing large-scale models is incredible, I will discuss what ought to be done in consequence. The line of argument is: large-scale models do perform useful forecasting and policy-analysis functions despite their incredible identification; the restrictions imposed in the usual style of identification are neither essential to constructing a model which can perform these functions nor innocuous; an alternative style of identification is available and practical. Finally we will look at some empirical work based on an alternative style of macroeconometrics. A six-variable dynamic system is estimated without using 1 Research for this paper was supported by NSF Grant Soc-76-02482. Lars Hansen executed the computations. The paper has benefited from comments by many people, especially Thomas J. Sargent

Endogenous Technological Change

Abstract: Growth in this model is driven by technological change that arises from intentional investment decisions made by profit maximizing agents. The distinguishing feature of the technology as an input is that it is neither a conventional good nor a public good; it is a nonrival, partially excludable good. Because of the nonconvexity introduced by a nonrival good, price-taking competition cannot be supported, and instead, the equilibriumis one with monopolistic competition. The main conclusions are that the stock of human capital determines the rate of growth, that too little human capital is devoted to research in equilibrium, that integration into world markets will increase growth rates, and that having a large population is not sufficient to generate growth.