The Measurement of Terms of Trade Effects

The change in goods and services available in a national economy brought about by the shifting of external price relationships is referred to as the terms of trade effects. This paper reviews the various methods which have been devised since the war to define and quantify such effects on the Gross National Product. The statistical annex shows that, as far as OECD countries are concerned, the differences between the various measures are not significant. Whereas the effects from terms of trade represented, on average, less than one half of one percent of the GNP of OECD countries during the 1960's the percentage has increased substantially since 1973, due most importantly to the increase in the oil price; by 1977 (on a 1970 price basis), it had reached 5 percent of GNP in Japan and up to 6 percent in Italy. On the other hand, the extreme case of Saudi Arabia where various formulas generate effects amounting to between one half and the whole of GNP, indicates that the measurement of terms of trade effects by various methods may give different results.