The paradoxical aspect of the Giffen Paradox is the inability of demand theory to explain why Giffen goods are apparently so rare. The resolution of the paradox arises from the distinction between the shape of market demand curves and the sequence of equilibrium prices that will be observed in markets in which quantity supplied changes. The sense in which the Giffen case is "unlikely" to occur is that the probability of identifying a Giffen good is less than the probability that such a good exists.

The paradoxical aspect of the Giffen Paradox is the inability of demand theory to explain why Giffen goods are apparently so rare. The resolution of the paradox arises from the distinction between the shape of market demand curves and the sequence of equilibrium prices that will be observed in markets in which quantity supplied changes. The sense in which the Giffen case is "unlikely" to occur is that the probability of identifying a Giffen good is less than the probability that such a good exists.

We examine the relation between inflation and nominal interest rates under the various monetary regimes in effect in the United States since the turn of the century. Our data include a newly constructed time series of short-term municipal bond yields observed annually since 1902. The results generally support the hypothesis that after-tax nominal yields adjust point-for-point with rationally forecasted inflation for the postwar years, but strongly reject that hypothesis for the preceding years. We suggest, and offer supporting evidence, that the difference between the two subperiods may be attributable to differences in the optimal forecasting technique for each era when forecasting is a costly endeavor.