Robert Lucas
Citation: For having developed and applied the hypothesis of rational expectations, and thereby having transformed macroeconomic analysis and deepened our understanding of economic policy.
The key idea
Rational expectations: people use all available information to form forecasts, including forecasts of policy. Policy that exploits expectational mistakes is therefore self-defeating once people learn.
The explanation
Lucas's 1972 paper formalised rational expectations in a monetary business-cycle model: anticipated monetary expansion has no real effects, only unanticipated changes do. His 1976 'Lucas Critique' demolished policy evaluation that used estimated econometric models — because the coefficients themselves depend on the policy regime, they shift when policy changes.
Why Africa should care
Every African central bank that anchors expectations through forward guidance is implementing a rational-expectations strategy. The credibility puzzle of inflation targeting in Ghana, Nigeria, and Kenya — where rates rise but inflation expectations don't fall — is a textbook Lucas-style outcome. The Lucas Critique invalidates much African policy evaluation that assumes 'historical regression coefficients' will hold under new policy regimes.
How to use it
When forecasting under a new policy regime, don't use coefficients estimated under the old regime without acknowledging the Lucas Critique. Structural modelling — deep parameters that don't shift — is the partial fix.
Canonical works
- Robert E. Lucas Jr. (1972) "Expectations and the Neutrality of Money" Journal of Economic Theory
- Robert E. Lucas Jr. (1976) "Econometric Policy Evaluation: A Critique" Carnegie-Rochester Conference Series
More from Information, finance, and development · 1990-1999
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- 1992Gary Becker
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- 1993Robert Fogel and Douglass North
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- 1994John Harsanyi, John Nash, and Reinhard Selten
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