Robust Monetary Policy with Imperfect Knowledge


Athanasios Orphanides

Download PDF
(378 KB)

2007-08 | April 1, 2007

We examine the performance and robustness properties of monetary policy rules in an estimated macroeconomic model in which the economy undergoes structural change and where private agents and the central bank possess imperfect knowledge about the true structure of the economy. Policymakers follow an interest rate rule aiming to maintain price stability and to minimize fluctuations of unemployment around its natural rate but are uncertain about the economy’s natural rates of interest and unemployment and how private agents form expectations. In particular, we consider two models of expectations formation: rational expectations and learning. We show that in this environment the ability to stabilize the real side of the economy is significantly reduced relative to an economy under rational expectations with perfect knowledge. Furthermore, policies that would be optimal under perfect knowledge can perform very poorly if knowledge is imperfect. Efficient policies that take account of private learning and misperceptions of natural rates call for greater policy inertia, a more aggressive response to inflation, and a smaller response to the perceived unemployment gap than would be optimal if everyone had perfect knowledge of the economy. We show that such policies are quite robust to potential misspecification of private sector learning and the magnitude of variation in natural rates.

Article Citation

Orphanides, Athanasios, and John C. Williams. 2007. “Robust Monetary Policy with Imperfect Knowledge,” Federal Reserve Bank of San Francisco Working Paper 2007-08. Available at

About the Author
John C. Williams served as President and Chief Executive Officer of the Federal Reserve Bank of San Francisco from March 1, 2011 to June 17, 2018. Dr. Williams was previously the executive vice president and director of research for the San Francisco bank, which he joined in 2002. He began his career in 1994 as an […] Learn more about John C. Williams