SIC and NAICS Codes
This is a repository of cleaned SIC Codes. The concordance files have multiple entries for mapping 2003 to 2017, which is fine but they have inconsistent or just mistyped descriptions which makes using them for processing difficult to say the least.
Some of those differences are just the addition of n.e.c. (not elsewhere classified), but sometimes there's different language descriptions. Where feasible I've gone with whichever description has greater clarity. Errors and Omissions are mine. Suggested updates are welcome.
I did a similar though easier job with the mapping of SIC to NAICS, again E&OE