IMF economist, Sam Ouliaris, defines an economic model as a simplified description of reality, designed to yield hypotheses about economic behavior that can be tested.
Ouliaris goes on to say:
“An important feature of an economic model is that it is necessarily subjective in design because there are no objective measures of economic outcomes. Different economists will make different judgments about what is needed to explain their interpretations of reality.
“There are two broad classes of economic models – theoretical and empirical. Theoretical models seek to derive verifiable implications about economic behavior under the assumption that agents maximize specific objectives subject to constraints that are well defined in the model (for example, an agent’s budget). They provide qualitative answers to specific questions – such as the implications of asymmetric information (when one side to a transaction knows more than the other) or how best to handle market failures.
“In contrast, empirical models aim to verify the qualitative predictions of theoretical models and convert these predictions to precise, numerical outcomes. For example, a theoretical model of an agent’s consumption behavior would generally suggest a positive relationship between expenditure and income. The empirical adaptation of the theoretical model would attempt to assign a numerical value to the average amount expenditure increases when income increases.
“Economic models generally consist of a set of mathematical equations that describe a theory of economic behavior. The aim of model builders is to include enough equations to provide useful clues about how rational agents behave or how an economy works. The structure of the equations reflects the model builder’s attempt to simplify reality – for example, by assuming an infinite number of competitors and market participants with perfect foresight. Economic models can be quite simple in practice: the demand for apples, for example, is inversely related to price if all other influences remain constant. The less expensive the apples, the more are demanded. Or models can be rather complex: some models that seek to predict the real level of output of an economy use thousands of complex formulations that go by such names as ‘nonlinear, interconnected differential equations.'”
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Sam Ouliaris (2011), What Are Economic Models?, Finance and Development, June 2011, Vol. 48, No. 2, at http://www.imf.org/external/pubs/ft/fandd/2011/06/basics.htm, accessed 30 April 2016.
Page created by: Ian Clark, last modified 30 April 2016.