Estimation of General and Commodity-Specific Inflation Rates Using Linear Time-Varying Constraints

In this paper, we consider the problem of estimating general and commodity-specific inflation rates by the stochastic approach considered in Clements and Izan (1987) and Selvanathan (1989). In order to achieve identification of commodity-specific rates, a linear constraint usually is imposed, and to make it operational, the constraint is generally imposed at an average over the time periods in the series. This paper uses recently developed methodology for estimation of econometric models with time-varying constraints (O’Donnel, Rambaldi, and Doran) to relax the constraint imposed at average shares and to derive commodity-specific inflation rates.