External Trade in Italy, 1922-38 .Some Evidence from Trade Index Numbers

This paper presents new estimates of value and quantity indices for Italian exter-nal trade in goods from 1922 to 1938, Trade in goods is defined so as to exclude transit trade and reparations but to include trade with the Itahan colornes and possessions. The quantity is defined as the net weight of the goods transferred or their number, and the urnt value as the value per unit of quantity. The constructed price and quantlty indi-ces are fixed-weighted indices. What ISTAT tells us about the construction of their trade series is not much and is not by any means clear. Firstly, we are told that the available ISTAT series is a sample senes and, 'although it is claimed that the sample is very lar-ge, we are not told the categories that have been left out. Secondly, the old unlt value figures are chain indices applied to the Laspeyres formula, using the previous quantities as weights; a procedure that can considearably distort the price changes. Thirdly, quan-tity indices are indirectly obtained by dividing total current value indices by unit value indices, a procedure which is not particular1y recommended.