Why are some NAICS codes only 5-digits long?
NAICS is a 6-digit code system. In developing NAICS, the United States, Canada, and Mexico agreed that the 5-digit codes would represent the level at which the system is comparable among the three countries. The sixth digit allows for each of the countries to have additional detail (i.e., subdivisions of a 5-digit category). In cases where the U.S. did not choose to create additional detail, the 5- and 6-digit categories within U.S. NAICS are the same, and the 6-digit US NAICS code ends in zero. In some hierarchical presentations, the 6-digit code is omitted where it is the same as the 5-digit category.
