Relative importance of sectoral and aggregate sources of price changes

This paper estimates a dynamic common factor model to assess relative importance of the aggregate and the sector-specific factors that determine changes in the prices of individual products. It also examines how aggregate price changes are affected by these factors. Two different specifications of the model are estimated: the baseline model with one aggregate factor, and a second specification with two aggregate factors. In the one-actor model, the aggregate factor contributes little to the movements of changes in prices, mostly of nondurable goods whereas it seems to have important contributions to the movements of changes in prices of commodity groups mainly used as intermediate or capital goods. In the specification with two aggregate factors, the additional factor has significant effects on changes in prices of ‘farm products’ and ‘processed foods and feeds’ only. Forecast-error variance decompositions of both aggregate and disaggregate price changes suggest that sectoral factors account for most of the variability at short horizons while the contributions of the aggregate factors increase as the time horizon lengthens. The results also show that sectoral factors are not only important for relative price changes but also have significant impact on aggregate inflation. The estimated common factors have statistically significant correlations with money growth and changes in the unemployment rate.