What´s Macro Policy: The Adaptive Expectations Theory

A theme that dominates modern discussions of macro policy is the importance of expectations, and economists have devoted a great deal of thought to expectations and the economy. Change in expectations can shift the aggregate demand (AD) curve; expectations of inflation can cause inflation. For this reason expectations are central to all policy discussions, and what people believe policy will be significantly influences the effectiveness of the policy.

Expectations complicate models and policymaking enormously; they change the focus of discussions from a response that can be captured by simple models to much more complicated discussions.

The adaptive expectations theory assumes people form their expectations on future inflation on the basis of previous and present inflation rates and only gradually change their expectations as experience unfolds. In this theory, there is a short-run tradeoff between inflation and unemployment which does not exist in the long-run. Any attempt to reduce the unemployment rate blow the natural rate sets in motion forces which destabilize the Phillips Curve and shift it rightward.

The Rational expectations model was developed by Robert Lucas,rational economic agents are assumed to make the best of all possible use of all publicly available information. Before reaching a conclusion, people are assumed to consider all available information before them, then make informed, rational judgments on what the future holds. This does not mean that every individual’s expectations or predictions about the future will be correct. Those errors that do occur will be randomly distributed, such that the expectations of large numbers of people will average out to be correct.

To illustrate

Expectations of inflatio...

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..., monetary and fiscal policy will work in different ways. People aren’t stupid and they aren’t super intelligent; they are people. If the government uses an activist monetary and fiscal policy in a predictable way, people will eventually come to build that expectation into their behavior. If the government bases its prediction of the effect of policy on past experience, that prediction will likely be wrong. But government never knows when expectations will change.

Let’s consider an example. Say that everyone expects government to run expansionary fiscal policy if the economy is in recession. In the absence of any expected policy response from the government, people will lower their prices when they see a recession coming. Expecting government expansionary policy, however they won’t lower their price. Thus, the expectation of policy can create its own problems.