Part of a series on |
Multi-agent systems |
---|
Multi-agent simulation |
Agent-oriented programming |
Related |
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. [1] 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. [2] Such rules could also be the result of optimization, realized through use of AI methods (such as Q-learning and other reinforcement learning techniques). [3]
The theoretical assumption of mathematical optimization by agents in equilibrium is replaced by the less restrictive postulate of agents with bounded rationality adapting to market forces. [4] ACE models apply numerical methods of analysis to computer-based simulations of complex dynamic problems for which more conventional methods, such as theorem formulation, may not find ready use. [5] Starting from initial conditions specified by the modeler, the computational economy evolves over time as its constituent agents repeatedly interact with each other, including learning from interactions. In these respects, ACE has been characterized as a bottom-up culture-dish approach to the study of economic systems. [6]
ACE has a similarity to, and overlap with, game theory as an agent-based method for modeling social interactions. [7] But practitioners have also noted differences from standard methods, for example in ACE events modeled being driven solely by initial conditions, whether or not equilibria exist or are computationally tractable, and in the modeling facilitation of agent autonomy and learning. [8]
The method has benefited from continuing improvements in modeling techniques of computer science and increased computer capabilities. The ultimate scientific objective of the method is to "test theoretical findings against real-world data in ways that permit empirically supported theories to cumulate over time, with each researcher’s work building appropriately on the work that has gone before." [9] The subject has been applied to research areas like asset pricing, [10] energy systems, [11] competition and collaboration, [12] transaction costs, [13] market structure and industrial organization and dynamics, [14] welfare economics, [15] and mechanism design, [16] information and uncertainty, [17] macroeconomics, [18] and Marxist economics. [19] [20]
The "agents" in ACE models can represent individuals (e.g. people), social groupings (e.g. firms), biological entities (e.g. growing crops), and/or physical systems (e.g. transport systems). The ACE modeler provides the initial configuration of a computational economic system comprising multiple interacting agents. The modeler then steps back to observe the development of the system over time without further intervention. In particular, system events should be driven by agent interactions without external imposition of equilibrium conditions. [21] Issues include those common to experimental economics in general [22] and development of a common framework for empirical validation [23] and resolving open questions in agent-based modeling. [24]
ACE is an officially designated special interest group (SIG) of the Society for Computational Economics. [25] Researchers at the Santa Fe Institute have contributed to the development of ACE.
One area where ACE methodology has frequently been applied is asset pricing. W. Brian Arthur, Eric Baum, William Brock, Cars Hommes, and Blake LeBaron, among others, have developed computational models in which many agents choose from a set of possible forecasting strategies in order to predict stock prices, which affects their asset demands and thus affects stock prices. These models assume that agents are more likely to choose forecasting strategies which have recently been successful. The success of any strategy will depend on market conditions and also on the set of strategies that are currently being used. These models frequently find that large booms and busts in asset prices may occur as agents switch across forecasting strategies. [10] [26] [27] More recently, Brock, Hommes, and Wagener (2009) have used a model of this type to argue that the introduction of new hedging instruments may destabilize the market, [28] and some papers have suggested that ACE might be a useful methodology for understanding the 2008 financial crisis. [29] [30] [31] See also discussion under Financial economics § Financial markets and § Departures from rationality.
Political economy is a branch of political science and economics studying economic systems and their governance by political systems. Widely studied phenomena within the discipline are systems such as labour markets and financial markets, as well as phenomena such as growth, distribution, inequality, and trade, and how these are shaped by institutions, laws, and government policy. Originating in the 18th century, it is the precursor to the modern discipline of economics. Political economy in its modern form is considered an interdisciplinary field, drawing on theory from both political science and modern economics.
In economics, industrial organization is a field that builds on the theory of the firm by examining the structure of firms and markets. Industrial organization adds real-world complications to the perfectly competitive model, complications such as transaction costs, limited information, and barriers to entry of new firms that may be associated with imperfect competition. It analyzes determinants of firm and market organization and behavior on a continuum between competition and monopoly, including from government actions.
Public choice, or public choice theory, is "the use of economic tools to deal with traditional problems of political science." It includes the study of political behavior. In political science, it is the subset of positive political theory that studies self-interested agents and their interactions, which can be represented in a number of ways—using standard constrained utility maximization, game theory, or decision theory. It is the origin and intellectual foundation of contemporary work in political economy.
Monetary economics is the branch of economics that studies the different theories of money: it provides a framework for analyzing money and considers its functions, and it considers how money can gain acceptance purely because of its convenience as a public good. The discipline has historically prefigured, and remains integrally linked to, macroeconomics. This branch also examines the effects of monetary systems, including regulation of money and associated financial institutions and international aspects.
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.
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.
Philosophy and economics studies topics such as public economics, behavioural economics, rationality, justice, history of economic thought, rational choice, the appraisal of economic outcomes, institutions and processes, the status of highly idealized economic models, the ontology of economic phenomena and the possibilities of acquiring knowledge of them.
Economic methodology is the study of methods, especially the scientific method, in relation to economics, including principles underlying economic reasoning. In contemporary English, 'methodology' may reference theoretical or systematic aspects of a method. Philosophy and economics also takes up methodology at the intersection of the two subjects.
Economics education or economic education is a field within economics that focuses on two main themes:
Cultural economics is the branch of economics that studies the relation of culture to economic outcomes. Here, 'culture' is defined by shared beliefs and preferences of respective groups. Programmatic issues include whether and how much culture matters as to economic outcomes and what its relation is to institutions. As a growing field in behavioral economics, the role of culture in economic behavior is increasingly being demonstrated to cause significant differentials in decision-making and the management and valuation of assets.
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.
Leigh Tesfatsion is a computational economist who taught at Iowa State University. She received her doctorate at the University of Minnesota, and taught at the University of Southern California before moving to Iowa State. She is known for promoting agent-based models as an alternative to rational expectations general equilibrium models for studying markets, finance, and macroeconomic phenomena. Her works are widely cited in the literature on the subject.
Kenneth Lewis Judd is a computational economist at Stanford University, where he is the Paul H. Bauer Senior Fellow at the Hoover Institution. He received his PhD in economics from the University of Wisconsin in 1980. He is perhaps best known as the author of Numerical Methods in Economics, and he is also among the editors of the Handbook of Computational Economics and of the Journal of Economic Dynamics and Control.
John Duffy is an American economist. He is a professor of economics at the University of California, Irvine.
Altreva Adaptive Modeler is a software application for creating agent-based financial market simulation models for the purpose of forecasting prices of real world market traded stocks or other securities. The technology it uses is based on the theory of agent-based computational economics (ACE), the computational study of economic processes modeled as dynamic systems of interacting heterogeneous agents.
Mathematical economics is the application of mathematical methods to represent theories and analyze problems in economics. Often, these applied methods are beyond simple geometry, and may include differential and integral calculus, difference and differential equations, matrix algebra, mathematical programming, or other computational methods. Proponents of this approach claim that it allows the formulation of theoretical relationships with rigor, generality, and simplicity.
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 methodology of econometrics is the study of the range of differing approaches to undertaking econometric analysis.
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.