An empirical analysis of real commodity price trends: Aggregation, model selection and implications

Abstract

This paper re-examines the empirical validity of the Prebish-Singer hypothesis of a secular decline in the relative price of primary commodities in terms of manufacturing goods. The empirical findings based on arithmetic and geometric commodity price indices are compared. When Grilli-Yang's arithmetic mean index is employed, the findings regarding commodity price trends are inconclusive. A new geometric mean index, in contrast, yields results that are robust.