In economics, an agent is an actor (more specifically, a decision maker) in a model of some aspect of the economy. Typically, every agent makes decisions by solving a well- or ill-defined optimization or choice problem.
For example, buyers (consumers) and sellers (producers) are two common types of agents in partial equilibrium models of a single market. Macroeconomic models, especially dynamic stochastic general equilibrium models that are explicitly based on microfoundations, often distinguish households, firms, and governments or central banks as the main types of agents in the economy. Each of these agents may play multiple roles in the economy; households, for example, might act as consumers, as workers, and as voters in the model. Some macroeconomic models distinguish even more types of agents, such as workers and shoppers [1] or commercial banks. [2]
The term agent is also used in relation to principal–agent models; in this case, it refers specifically to someone delegated to act on behalf of a principal. [3]
In agent-based computational economics, corresponding agents are "computational objects modeled as interacting according to rules" over space and time, not real people. The rules are formulated to model behavior and social interactions based on stipulated incentives and information. [4] The concept of an agent may be broadly interpreted to be any persistent individual, social, biological, or physical entity interacting with other such entities in the context of a dynamic multi-agent economic system.
An economic model in which all agents of a given type (such as all consumers, or all firms) are assumed to be exactly identical is called a representative agent model. A model which recognizes differences among agents is called a heterogeneous agent model. Economists often use representative agent models when they want to describe the economy in the simplest terms possible. In contrast, they may be obliged to use heterogeneous agent models when differences among agents are directly relevant for the question at hand. [5] For example, considering heterogeneity in age is likely to be necessary in a model used to study the economic effects of pensions; [6] considering heterogeneity in wealth is likely to be necessary in a model used to study precautionary saving [7] or redistributive taxation. [8]
Economics is a social science that studies the production, distribution, and consumption of goods and services.
Macroeconomics is a branch of economics that deals with the performance, structure, behavior, and decision-making of an economy as a whole. This includes national, regional, and global economies. Macroeconomists study topics such as output/GDP and national income, unemployment, price indices and inflation, consumption, saving, investment, energy, international trade, and international finance.
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 with the theory of partial equilibrium, which analyzes a specific part of an economy while its other factors are held constant. In general equilibrium, constant influences are considered to be noneconomic, or in other words, considered to be beyond the scope of economic analysis. The noneconomic influences may change given changes in the economic factors however, and therefore the prediction accuracy of an equilibrium model may depend on the independence of the economic factors from noneconomic ones.
New Keynesian economics is a school of 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.
Experimental economics is the application of experimental methods to study economic questions. Data collected in experiments are used to estimate effect size, test the validity of economic theories, and illuminate market mechanisms. Economic experiments usually use cash to motivate subjects, in order to mimic real-world incentives. Experiments are used to help understand how and why markets and other exchange systems function as they do. Experimental economics have also expanded to understand institutions and the law.
Economists use the term representative agent to refer to the typical decision-maker of a certain type.
A macroeconomic model is an analytical tool designed to describe the operation of the problems of economy of a country or a region. These models are usually designed to examine the comparative statics and dynamics of aggregate quantities such as the total amount of goods and services produced, total income earned, the level of employment of productive resources, and the level of prices.
Computational economics is an interdisciplinary research discipline that combines methods in computational science and economics to solve complex economic problems. This subject encompasses computational modeling of economic systems. Some of these areas are unique, while others established areas of economics by allowing robust data analytics and solutions of problems that would be arduous to research without computers and associated numerical methods.
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.
Mainstream economics is the body of knowledge, theories, and models of economics, as taught by universities worldwide, that are generally accepted by economists as a basis for discussion. Also known as orthodox economics, it can be contrasted to heterodox economics, which encompasses various schools or approaches that are only accepted by a minority of economists.
In economics, an aggregate is a summary measure. It replaces a vector that is composed of many real numbers by a single real number, or a scalar. Consequently, there occur various problems that are inherent in the formulations that use aggregated variables.
Agent-based computational economics (ACE) is the area of computational economics that studies economic processes, including whole economies, as dynamic systems of interacting agents. As such, it falls in the paradigm of complex adaptive systems. In corresponding agent-based models, the "agents" are "computational objects modeled as interacting according to rules" over space and time, not real people. The rules are formulated to model behavior and social interactions based on incentives and information. Such rules could also be the result of optimization, realized through use of AI methods.
Dynamic stochastic general equilibrium modeling is a macroeconomic method which is often employed by monetary and fiscal authorities for policy analysis, explaining historical time-series data, as well as future forecasting purposes. DSGE econometric modelling applies general equilibrium theory and microeconomic principles in a tractable manner to postulate economic phenomena, such as economic growth and business cycles, as well as policy effects and market shocks.
Microfoundations are an effort to understand macroeconomic phenomena in terms of economic agents' behaviors and their interactions. Research in microfoundations explores the link between macroeconomic and microeconomic principles in order to explore the aggregate relationships in macroeconomic models.
Per Lennart Krusell, born 1959, is a Swedish macroeconomic theorist who is currently the Torsten and Ragnar Soderberg Chair in Economics and the Institute for International Economic Studies, Stockholm University, as well as Centennial Professor of Economics at the London School of Economics.
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.
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.
Truman Fassett Bewley is an American economist. He is the Alfred Cowles Professor of Economics at Yale University. Originally specializing in mathematical economics and general equilibrium theory, since the late 1990s Bewley has gained renown for his work on sticky wages. In Bewley's 1999 book Why Wages Don't Fall During a Recession, hundreds of interviews with executives, labor leaders, and other professionals establish morale as an important factor in why businesses are reluctant to decrease employee compensation at times of low demand.
In economic theory and econometrics, the term heterogeneity refers to differences across the units being studied. For example, a macroeconomic model in which consumers are assumed to differ from one another is said to have heterogeneous agents.
Optimal capital income taxation is a subarea of optimal tax theory which studies the design of taxes on capital income such that a given economic criterion like utility is optimized.