14. Statistics is necessary to cau tion persons against the use of these trade statistics for purposes of comparison between nations. The meth ods of arriving at the value of imports and exports are far from uniform in the different countries. In the statistics of the United States the value of the im ported goods at the port of lading is shown. This same method is followed in the statistics of Canada, Cuba, Mexico, the Philippine Islands and British South America. Other countries express their sta tistics in terms of the value of the goods in the port of arrival. This method is followed in Bulgaria, Por tugal, Russia, Serbia, Sweden, Turkey, United King dom, Brazil, British India, Ceylon, China, Japan, Persia, Siam and New Zealand. In others an arbi trary percentage is added to the value at the port of lading in order to determine the value in the port of arrival. Australia adds 10 per cent to the invoice value to obtain the value in her own ports. Belgium, Germany, Italy, Norway, Switzerland, Egypt, and sonic of the newer states place an official valuation on imports. These official valuations may be quite at variance with the real value of goods. The matter is even more complicated by the fact that some of these countries use different official valuations for each country of origin. France, Roumania and Spain ap ply the same official valuation to all countries.
Export statistics are subject to similar variations. Since export duties are not frequent and the customs officials show little interest in the gathering of export statistics, these latter are even more unreliable than import figures. The information in regard to the
countries of origin or of destination is to be taken as only approximately correct. While goods shipped from New York to Rotterdam may be intended for re-export to Belgium or Russia, there may be noth ing in the invoice or the export declaration to show any such intention. In the exports of many coun tries of Europe are goods which could not possibly have been produced within these countries yet they figure in statistics as exports from those lands. This is especially the case in some of the South American countries where imported goods which have changed form in some slight way, are henceforth regarded as produced within the country and when re-exported are charged export duties as goods manufactured within the country.
Another difficulty confronts one who attempts to compare imports and exports of specific products of any one country. The figures published by the United States Government are gathered with no at tempt to make them comparable. Imports may be given in dollars and pounds, exports in pieces or some other measurement, making accurate coordination im possible.
Trade statistics should, therefore, be used with the greatest care and the conclusions based on them care fully verified. Nevertheless, the fact that it is diffi cult to arrive at conclusions should not obscure the supreme importance of a study of international trade relations.