The Role of Inflation Uncertainty in Germany: Friedman's Hypothesis Revisited.

The paper reconsiders Friedman's (1977) proposition that increased inflation uncertainty may have adverse real effects for the German case. A proxy for the unobservable uncertainty variable is obtained from the Kalman-filtering estimation of a time-varying parameter model of inflation. The measure is introduced into an output equation that also includes anticipated and unanticipated inflation, thus allowing tests of both the Friedman and the Macro Rational Expectations hypotheses. The empirical evidence does not provide strong support for Friedman's view. Unanticipated inflation, on the other hand, seems to play a significant role for German output growth in the short run.