On The Biases In Foreign Trade Indices

Starting out from the observation that both imports and exports may be viewed as the difference between domestic consumption (use) and production, static standard theory of biases in consumption and production indices is brought to bear upon trade indices: Laspeyres tends to overrate when applied to imports and to underrate when applied to exports; for Paasche, the opposite holds true. Hence, terms of trade tend to be underrated (exaggerated) when based upon Laspeyres (Paasche) price indices. The problem of extending these conclusions to the case of changes in production frontiers and preference maps is discussed. When homotheticity is absent, correlation between price and quantity relatives may upset the simple conclusions. This is of special importance in the large‐country situation. Dynamics further complicate the situation. A cobweb mechanism in exports may thus reverse the static results.