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The overlapping generations (OLG) model is one of the dominating frameworks of analysis in the study of macroeconomic dynamics and economic growth. In contrast, to the Ramsey–Cass–Koopmans neoclassical growth model in which individuals are infinitely-lived, in the OLG model individuals live a finite length of time, long enough to overlap with at least one period of another agent's life.
Economic growth is the increase in the inflation-adjusted market value of the goods and services produced by an economy over time. It is conventionally measured as the percent rate of increase in real gross domestic product, or real GDP.
The Ramsey–Cass–Koopmans model, or Ramsey growth model, is a neoclassical model of economic growth based primarily on the work of Frank P. Ramsey, with significant extensions by David Cass and Tjalling Koopmans. The Ramsey–Cass–Koopmans model differs from the Solow–Swan model in that the choice of consumption is explicitly microfounded at a point in time and so endogenizes the savings rate. As a result, unlike in the Solow–Swan model, the saving rate may not be constant along the transition to the long run steady state. Another implication of the model is that the outcome is Pareto optimal or Pareto efficient.
The OLG model is the natural framework for the study of: (a) the life-cycle behavior (investment in human capital, work and saving for retirement), (b) the implications of the allocation of resources across the generations, such as Social Security, on the income per capita in the long-run,(c) the determinates of economic growth in the course of human history, and (d) the factors that triggered the fertility transition.
Human capital is the stock of habits, knowledge, social and personality attributes embodied in the ability to perform labour so as to produce economic value.
Retirement is the withdrawal from one's position or occupation or from one's active working life. A person may also semi-retire by reducing work hours.
In economics, resource allocation is the assignment of available resources to various uses. In the context of an entire economy, resources can be allocated by various means, such as markets or planning.
The construction of the OLG model was inspired by Irving Fisher's monograph The Theory of Interest.It was first formulated in 1947, in the context of a pure-exchange economy, by Maurice Allais, and more rigorously by Paul Samuelson in 1958. In 1965, Peter Diamond incorporated an aggregate neoclassical production into the model. This OLG model with production was further augmented with the development of the two-sector OLG model by Oded Galor, and the introduction of OLG models with endogenous fertility.
Irving Fisher was an American economist, statistician, inventor, and Progressive social campaigner. He was one of the earliest American neoclassical economists, though his later work on debt deflation has been embraced by the post-Keynesian school. Joseph Schumpeter described him as "the greatest economist the United States has ever produced", an assessment later repeated by James Tobin and Milton Friedman.
Maurice Félix Charles Allais was a French physicist and economist, the 1988 winner of the Nobel Memorial Prize in Economic Sciences "for his pioneering contributions to the theory of markets and efficient utilization of resources", for Maurice Allais contribution, along with John Hicks and Paul Samuelson, to neoclassical synthesis. They formalize the self-regulation of markets, that Keynes refuted, while reiterating some of his ideas.
Paul Anthony Samuelson was an American economist. The first American to win the Nobel Memorial Prize in Economic Sciences, the Swedish Royal Academies stated, when awarding the prize in 1970, that he "has done more than any other contemporary economist to raise the level of scientific analysis in economic theory". Economic historian Randall E. Parker has called him the "Father of Modern Economics", and The New York Times considered him to be the "foremost academic economist of the 20th century".
Books devoted to the use of the OLG model include Azariadis' Intertemporal Macroeconomicsand de la Croix and Michel's Theory of Economic Growth.
Constantine Christos "Costas" Azariadis is a macroeconomist born in Athens, Greece. He has worked on numerous topics, such as labor markets, business cycles, and economic growth and development. Azariadis originated and developed implicit contract theory.
David de la Croix is a Belgian scholar and author in the field of economic growth and demographic economics. He is professor at the University of Louvain (UCLouvain).
Philippe Michel was a French mathematical economist.
The most basic OLG model has the following characteristics:
The pure-exchange OLG model was augmented with the introduction of an aggregate neoclassical production by Peter Diamond.In contrast, to Ramsey–Cass–Koopmans neoclassical growth model in which individuals are infinitely-lived and the economy is characterized by a unique steady-state equilibrium, as was established by Oded Galor and Harl Ryder, the OLG economy may be characterized by multiple steady-state equilibria, and initial conditions may therefore affect the long-run evolution of the long-run level of income per capita.
Peter Arthur Diamond is an American economist known for his analysis of U.S. Social Security policy and his work as an advisor to the Advisory Council on Social Security in the late 1980s and 1990s. He was awarded the Nobel Memorial Prize in Economic Sciences in 2010, along with Dale T. Mortensen and Christopher A. Pissarides. He is an Institute Professor at the Massachusetts Institute of Technology. On June 6, 2011, he withdrew his nomination to serve on the Federal Reserve's board of governors, citing intractable Republican opposition for 14 months.
Since initial conditions in the OLG model may affect economic growth in long-run, the model was useful for the exploration of the convergence hypothesis.
The economy has the following characteristics:
The one-sector OLG model was further augmented with the introduction of a two-sector OLG model by Oded Galor.The two-sector model provides a framework of analysis for the study of the sectoral adjustments to aggregate shocks and implications of international trade for the dynamics of comparative advantage. In contrast to the Uzawa two-sector neoclassical growth model, the two-sector OLG model may be characterized by multiple steady-state equilibria, and initial conditions may therefore affect the long-run position of an economy.
Oded Galor and his co-authors develop OLG models where population growth is endogenously determined to explore: (a) the importance the narrowing of the gender wage gap for the fertility decline,(b) the contribution of the rise in the return to human capital and the decline in fertility to the transition from stagnation to growth, and (c) the importance of population adjustment to technological progress for the emergence of the Malthusian trap.
One important aspect of the OLG model is that the steady state equilibrium need not be efficient, in contrast to general equilibrium models where the First Welfare Theorem guarantees Pareto efficiency. Because there are an infinite number of agents in the economy (summing over future time), the total value of resources is infinite, so Pareto improvements can be made by transferring resources from each young generation to the current old generation. Not every equilibrium is inefficient; the efficiency of an equilibrium is strongly linked to the interest rate and the Cass Criterion gives necessary and sufficient conditions for when an OLG competitive equilibrium allocation is inefficient.
Another attribute of OLG type models is that it is possible that 'over saving' can occur when capital accumulation is added to the model—a situation which could be improved upon by a social planner by forcing households to draw down their capital stocks. [ citation needed ]However, certain restrictions on the underlying technology of production and consumer tastes can ensure that the steady state level of saving corresponds to the Golden Rule savings rate of the Solow growth model and thus guarantee intertemporal efficiency. Along the same lines, most empirical research on the subject has noted that oversaving does not seem to be a major problem in the real world.
In Diamond's version of the model, individuals tend to save more than is socially optimal, leading to dynamic inefficiency. Subsequent work has investigated whether dynamic inefficiency is a characteristic in some economies [ citation needed ].and whether government programs to transfer wealth from young to poor do reduce dynamic inefficiency
Another fundamental contribution of OLG models is that they justify existence of money as a medium of exchange. A system of expectations exists as an equilibrium in which each new young generation accepts money from the previous old generation in exchange for consumption. They do this because they expect to be able to use that money to purchase consumption when they are the old generation.
In economics, general equilibrium theory attempts to explain the behavior of supply, demand, and prices in a whole economy with several or many interacting markets, by seeking to prove that the interaction of demand and supply will result in an overall general equilibrium. General equilibrium theory contrasts to the theory of partial equilibrium, which only analyzes single markets.
New Keynesian economics is a school of contemporary macroeconomics that strives to provide microeconomic foundations for Keynesian economics. It developed partly as a response to criticisms of Keynesian macroeconomics by adherents of new classical macroeconomics.
This aims to be a complete article list of economics topics:
Evolutionary economics is part of mainstream economics as well as a heterodox school of economic thought that is inspired by evolutionary biology. Much like mainstream economics, it stresses complex interdependencies, competition, growth, structural change, and resource constraints but differs in the approaches which are used to analyze these phenomena.
Nominal rigidity, also known as price-stickiness or wage-stickiness, is a situation in which a nominal price is resistant to change. Complete nominal rigidity occurs when a price is fixed in nominal terms for a relevant period of time. For example, the price of a particular good might be fixed at $10 per unit for a year. Partial nominal rigidity occurs when a price may vary in nominal terms, but not as much as it would if perfectly flexible. For example, in a regulated market there might be limits to how much a price can change in a given year.
The Solow–Swan model is an economic model of long-run economic growth set within the framework of neoclassical economics. It attempts to explain long-run economic growth by looking at capital accumulation, labor or population growth, and increases in productivity, commonly referred to as technological progress. At its core is a neoclassical (aggregate) production function, often specified to be of Cobb–Douglas type, which enables the model "to make contact with microeconomics". The model was developed independently by Robert Solow and Trevor Swan in 1956, and superseded the Keynesian Harrod–Domar model.
David Cass was a professor of economics at the University of Pennsylvania, mostly known for his contributions to general equilibrium theory. His most famous work was on the Ramsey–Cass–Koopmans model of economic growth.
Robert Graham King is an American macroeconomist. He is currently Professor at the Department of Economics at Boston University, editor of the Journal of Monetary Economics, research consultant to the Federal Reserve Bank of Richmond, and a member of the National Bureau of Economic Research.
New classical macroeconomics, sometimes simply called new classical economics, is a school of thought in macroeconomics that builds its analysis entirely on a neoclassical framework. Specifically, it emphasizes the importance of rigorous foundations based on microeconomics, especially rational expectations.
Oded Galor is an Israeli economist who is currently Herbert H. Goldberger Professor of Economics at Brown University. He is the founder of unified growth theory. Galor has contributed to the understanding of process of development over the entire course of human history and the role of deep-rooted factors in the transition from stagnation to growth and in the emergence of the vast inequality across the globe. Moreover, he has pioneered the exploration of the impact of human evolution, population diversity, and inequality on the process of development over most of human existence.
The Cass criterion, also known as the Malinvaud–Cass criterion, is a central result in theory of overlapping generations models in economics. It is named after David Cass.
Unified growth theory was developed in light of the failure of endogenous growth theory to capture key empirical regularities in the growth processes and their contribution to the momentous rise in inequality across nations in the past two centuries. Unlike earlier growth theories that have focused entirely on the modern growth regime, unified growth theory captures the growth process over the entire course of human existence, highlighting the critical role of the differential timing of the transition from Malthusian stagnation to sustained economic growth in the emergence of inequality across countries and regions.
In economics, dynamic efficiency is a situation where it is impossible to make one generation better off without making any other generation worse off. It is closely related to the notion of "golden rule of saving". In general, an economy will fail to be dynamically efficient if the real interest rate is below the growth rate of the economy.
Macroeconomic theory has its origins in the study of business cycles and monetary theory. In general, early theorists believed monetary factors could not affect real factors such as real output. John Maynard Keynes attacked some of these "classical" theories and produced a general theory that described the whole economy in terms of aggregates rather than individual, microeconomic parts. Attempting to explain unemployment and recessions, he noticed the tendency for people and businesses to hoard cash and avoid investment during a recession. He argued that this invalidated the assumptions of classical economists who thought that markets always clear, leaving no surplus of goods and no willing labor left idle.
The AK model of economic growth is an endogenous growth model used in the theory of economic growth, a subfield of modern macroeconomics. In the 1980s it became progressively clearer that the standard neoclassical exogenous growth models were theoretically unsatisfactory as tools to explore long run growth, as these models predicted economies without technological change and thus they would eventually converge to a steady state, with zero per capita growth. A fundamental reason for this is the diminishing return of capital; the key property of AK endogenous-growth model is the absence of diminishing returns to capital. In lieu of the diminishing returns of capital implied by the usual parameterizations of a Cobb–Douglas production function, the AK model uses a linear model where output is a linear function of capital. Its appearance in most textbooks is to introduce endogenous growth theory.
The Journal of Economic Growth is a peer-reviewed academic journal covering research in economic growth and dynamic macroeconomics. It was established in 1996 and is published by Springer Science+Business Media. The journal deals with both theories and their empirics, and examines the entire array of subject areas in economic growth, including neoclassical and endogenous growth models, growth and income distribution, human capital, fertility, trade, development, migration, money, the political economy, endogenous technological change, overlapping-generations models, and economic fluctuations.
The Cambridge capital controversy, sometimes called "the capital controversy" or "the two Cambridges debate", was a dispute between proponents of two differing theoretical and mathematical positions in economics that started in the 1950s and lasted well into the 1960s. The debate concerned the nature and role of capital goods and a critique of the neoclassical vision of aggregate production and distribution. The name arises from the location of the principals involved in the controversy: the debate was largely between economists such as Joan Robinson and Piero Sraffa at the University of Cambridge in England and economists such as Paul Samuelson and Robert Solow at the Massachusetts Institute of Technology, in Cambridge, Massachusetts.
The Galor-Zeira model is the first macroeconomic model to explore the role of heterogeneity in the determination of macroeconomic behavior. In contrast to the representative agent approach that dominated the field of macroeconomics till the early 1990s and argued that heterogeneity has no impact on macroeconomic activity, the model demonstrates that in the presence of capital markets imperfections and local non-convexities in the production of human capital, income distribution affects the long run level of income per-capita as well as the growth process.