The origins of international price and volume comparisons of GDP can be traced back to the experimental comparisons carried out by the Organisation for European Economic Cooperation (OEEC) in the 1950s. Two approaches were adopted. The first was a comparison made from the expenditure side using mainly price data. Initially, it covered France, Germany, Italy, the United Kingdom and the United States.1 Subsequently, it was expanded to include Belgium, Denmark, the Netherlands and Norway.2 The second was a comparison between the United Kingdom and the United States made from the production side using mainly quantity data.