Why do the exports of country A to country B not equal to the imports of country B from country A in the Direction of Trade Statistics (DOTS) dataset?

It is sometimes assumed that corresponding export and import data between partner countries should be consistent. That is, the exports from Country A to B should be equal to the imports of Country B from A, after taking into account the insurance and freight costs under the generally observed case that Country B imports are valued on a cost, insurance, freight (c.i.f.) basis. The DOTS estimation system uses this assumption in cases where one partner has not reported data.

However, notwithstanding the inclusion of insurance and freight in imports c.i.f., it should be noted that there are several complications that can cause inconsistency between exports to a partner and the partner�s recorded imports f.o.b., or between imports free on board (f.o.b.) from a partner and the partner�s recorded exports. The principal reasons for inconsistent statistics on destination and origin for a given shipment are differences in 1) classification concepts and detail, 2) time of recording, 3) valuation, and 4) coverage, as well as 5) processing errors.

The DOTS dataset can be found here.

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