How Useful is the Concept of the Natural Real Rate of Interest for Monetary Policy?

The natural rate of interest plays a key role in Wicksell's cumulative process as well as in modern monetary equilibrium models of the business cycle. It constitutes a useful concept for the theoretical analysis of the interdependence of monetary policy and economic fluctuations. However, the usefulness of this concept for the practice of monetary policy is limited-especially owing to the fact that the natural real rate of interest and its law of motion cannot be measured with satisfying precision