A Note On Monetary Policy, Asset Prices, And Model Uncertainty

Using a macroeconomic model with asset prices, we analyze how optimal monetary policy and macroeconomic dynamics and performance are affected by a central bank's desire to be robust against model misspecifications. We show that a higher central bank preference for robustness implies a more aggressive reaction of the nominal interest rate to the expected future inflation rate and inflation shocks. The dynamic stability of the equilibrium is not modified for a sufficiently high preference for robustness. However, the speed of dynamic convergence is lower under robust control compared to a benchmark case without it and implies supplementary economic costs. Finally, an increase in the preference for robustness comes at the cost of higher macroeconomic and financial volatility in the presence of inflation shocks. It has no effect on the reaction of inflation, output gap, and asset price gap to shocks affecting goods and financial markets.