Follow one component through two borders
In a simplified chain, economy A supplies a component worth €40 to B. B adds €60 of local value and exports the finished item to C for €100. The two recorded export flows total €140 even though the final item is worth €100. For B, gross exports are €100 and net exports from these two flows are €60. In this deliberately simple case, that equals B’s domestic value added in the exported item. It is not a general identity: imports for domestic consumption, inventories and other trade flows break the equivalence.
Choose the right exposure
For a near-term port disruption, gross shipment volumes may be the most useful indicator because the entire consignment must cross the affected border. For income exposure to weaker final demand, ask which domestic industries supplied the labour, services and other value embodied in the final product. A service provider may have meaningful indirect export exposure without ever appearing as a goods exporter. Neither perspective by itself identifies the gross profit margin of a listed manufacturer.
Read the table before drawing a map
Value-added trade estimates combine national input-output tables and bilateral trade flows. They provide industry averages and are published with a lag. Compare the same edition, industry classification, country grouping and measure across periods. The last shipping destination can be a transit hub rather than the market of final use. Pair value-added estimates with current shipment statistics when timeliness matters, and keep their different units and dates visible.
Practical check
Write down whether the question concerns border throughput, the trade balance or income tied to final demand before choosing the series.