A number of observers have advocated recently that the Federal Reserve take an ``opportunistic'' approach to the conduct of monetary policy. A hallmark of this approach is that the central bank focuses on fighting inflation when inflation is high, but focuses on stabilizing output when inflation...

Using a dynamic linear equation that has a conditionally homoskedastic moving average disturbance, we compare two parameterizations of a commonly used instrumental variables estimator (Hansen (1982)) to one that is asymptotically optimal in a class of estimators that includes the conventional...