Last updated in 1987, this code is 'history', at least as far as most of the US federal government is concerned. In 1997 the implementation of a new code, NAICS, began, and the conversion was complete in 2004. However, commercial publishers are continuing to use SIC.
Here are some important things to know about SIC:
- Four-digit codes. The most specific and focused SIC codes are always four digits. However, sometimes you'll see codes labeled SIC, but which are shorter or longer. Here's why:
- 2-3 digit SIC codes: In order to group together data in similar focused industries, sometimes data will be presented at the truncated level of 2- or 3-digit codes.
- 5-6 digit SIC codes: Because of the SIC code's weaknesses, some commercial publishers have augmented the base SIC codes. Dun & Bradstreet and InfoUSA are two examples of companies that have done this.
- Primary SIC/NAICS codes: Please see discussion above.
- Who assigns SIC/NAICS codes? Please see discussion above.
- Weaknesses: SIC is weakest in the areas of the service industries and high-technology, in other words, not detailed enough.
- NEC or Not Elsewhere Classified: these are catch-all categories for industry groups that are somewhat significant, but not significant enough to warrant their own separate codes. A good example is SIC code 3469, "Metal Stampings, not elsewhere classified". Among other things, it includes such products as: ice cream dippers; stamped metal ashtrays; porcelain enameled cooking ware, store fronts, stove parts, and table tops; stamped metal floor tile; and electronic enclosures!
- Guiding principle: in the construction of the SIC code, the guiding principle was: to group together industries that have similar production processes. This means that the code reflects the viewpoint of producers rather than of consumers. (Be warned! This principle was not always consistently applied.) Here are a couple of examples where the principle has some weird side-effects:
- In SIC code 3751, motorcycles and bicycles are grouped together. Here you have two end products which are quite different, but grouped together in one code. This means that it is very difficult to find data on motorcycles only, or bicycles only: generally, you must go to trade associations for data.
- In contrast, there are two SIC codes for sugar production: one for sugar made from sugar cane (2061) and one for sugar made from sugar beets (2063). In this case, you have end products which are completely interchangeable as far as the consumer is concerned, but because the production processes are very different, there are two codes. This means that in order to find data about sugar production, either you must collect data for both SIC codes, or hope that you can find data collected at the truncated three-digit level.