Phillips curve. The message of the REH for econometrics was clear. By postulating that
economic agents form their expectations endogenously on the basis of the true model of
the economy and a correct understanding of the processes generating exogenous variables
of the model, including government policy, the REH raised serious doubts about the invariance
of the structural parameters of the mainstream macroeconometric models in the
face of changes in government policy. This was highlighted in Lucas’s critique of macroeconometric
policy evaluation. By means of simple examples Lucas (1976) showed that in
models with rational expectations the parameters of the decision rules of economic agents,
such as consumption or investment functions, are usually a mixture of the parameters of
the agents’ objective functions and of the stochastic processes they face as historically
given. Therefore, Lucas argued, there is no reason to believe that the ‘structure’ of the
decision rules (or economic relations) would remain invariant under a policy intervention.
The implication of the Lucas critique for econometric research was not, however, that
policy evaluation could not be done, but rather than the traditional econometric models
and methods were not suitable for this purpose. What was required was a separation of
the parameters of the policy rule from those of the economic model. Only when these
parameters could be identified separately given the knowledge of the joint probability
distribution of the variables (both policy and non-policy variables), would it be possible
to carry out an econometric analysis of alternative policy options
Phillips curve. The message of the REH for econometrics was clear. By postulating that
economic agents form their expectations endogenously on the basis of the true model of
the economy and a correct understanding of the processes generating exogenous variables
of the model, including government policy, the REH raised serious doubts about the invariance
of the structural parameters of the mainstream macroeconometric models in the
face of changes in government policy. This was highlighted in Lucas’s critique of macroeconometric
policy evaluation. By means of simple examples Lucas (1976) showed that in
models with rational expectations the parameters of the decision rules of economic agents,
such as consumption or investment functions, are usually a mixture of the parameters of
the agents’ objective functions and of the stochastic processes they face as historically
given. Therefore, Lucas argued, there is no reason to believe that the ‘structure’ of the
decision rules (or economic relations) would remain invariant under a policy intervention.
The implication of the Lucas critique for econometric research was not, however, that
policy evaluation could not be done, but rather than the traditional econometric models
and methods were not suitable for this purpose. What was required was a separation of
the parameters of the policy rule from those of the economic model. Only when these
parameters could be identified separately given the knowledge of the joint probability
distribution of the variables (both policy and non-policy variables), would it be possible
to carry out an econometric analysis of alternative policy options
การแปล กรุณารอสักครู่..
