Concordance between SITC Rev 2 at the 4-digit level 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 4digit 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.
The original NAICS contains some codes ending with “X” or “XX”. They were adjusted as
follows:
SITC Rev. 2 Original NAICS
Adjusted NAICS
0011
11211X
1121
0014
1123XX
1123
025
1123XX
1123
0484
31181X
3118
0611
31131X
3113
0612
31131X
3113
0613
31131X
3113
3510
22111X
2211
7132
33631X
33631