negative trend in the price of commodities in 1870-1945 implies an increasingly weak position for developing countries relative … of the price of the 24 most-traded commodities in 1900-92. The method they use tests for nonstationarity (unit roots) in …-Singer hypothesis though not universal, holds for most commodities. This evidence rejects, to some extent, previous evidence by …

evidence does not actually attempt to measure the volatility of prices of individual goods or commodities. The literature tends … to focus on trends in the evolution and volatility of ratios of price indexes composed of multiple commodities and … individual primary commodities are less volatile than those of individual manufactured goods. However, the challenges of managing …

main conclusions are: the timing and number of breaks in volatility vary considerably across individual commodities … commodities are the two world wars and the collapse of the Bretton-Woods system; and structural breaks marking increased price …