In: Economics
An economic model is a simplified description of reality,
designed to yield hypotheses about economic behavior that can be
tested. 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.”