SITC Rev 2 and NAICS (1997)

The basis for this concordance is the US import and export data in 1989, from the NBER website. The data sets contain trade data classified by 5-digit SITC Rev. 2 items and 6-digit NAICS industries. The 5-digit SITC Rev. 2 items are truncated into 4-digit subgroups. The 4- digit SITC Rev. 2 subgroups are matched, for exports and imports separately, to the 6-digit NAICS industry with the highest trade value. If the export and import matches agreed, we accepted that match. If they disagreed, the match to the largest sum of exports and imports was accepted. In some cases, the NAICS industry listing was truncated to 5 or occasionally 4 digits to encompass most trade, and to avoid NAICS categories used only by the United States. In a few cases, preference was given to more specific NAICS categories that matched the SITC definition over catchall NAICS categories.