Adaptive-regressive expectations and the price level: A reformulation

In a recent paper, Frenkel (1975) presents an adaptive-regressive scheme of expectations as applied to the inflation rate. While the rationale for the scheme is the presence of expectations concerning the price level, Frenkel's construction does not specify such an expected price level, but only a short-run (instantaneous) and a long-run expected inflation rate. It is shown here that, even though such a specification yields reasonable results for certain important kind of policy changes, it is not robust enough so as to yield equally reasonable outcomes for other type of changes. This paper presents a specification of the expected price level (and, consequently, of all future expected inflation rates) which is not subject to those shortcomings and which seems to reflect in a better manner the basic economic idea behind the scheme.