The Lucas critique and the stability of empirical models

"This paper re-considers the empirical relevance of the Lucas critique using a DSGE sticky price model in which a weak central bank response to inflation generates equilibrium indeterminacy. The model is calibrated on the magnitude of the historical shift in the Federal Reserve's policy rule and is capable of generating the decline in the volatility of inflation and real activity observed in U.S. data. Using Monte Carlo simulations and a backward-looking model of aggregate supply and demand, we show that shifts in the policy rule induce breaks in both the reduced-form coefficients and the reduced-form error variances. The statistics of popular parameter stability tests are shown to have low power if such heteroskedasticity is neglected. In contrast, when the instability of the reduced-form error variances is accounted for, the Lucas critique is found to be empirically relevant for both artificial and actual data."--Federal Reserve Bank of Richmond web site.