Data with more granular NAICS codes

Two questions, actually:

  1. Looking over the codes in the INDNAICS variable [https://usa.ipums.org/usa/volii/indcross03.shtml]

I’m confused as to why there seems to be a mix of 3, 4, and sometimes 5-digit NAICS codes.

Is this a partial list of all codes available via ACS? Or is the unerlying microdata really not consistent to a particular NAICS level (3-digit sector, 4-digit industry groups, 5 or 6-digit industries?)

  1. Are there other surveys with more granular NAICS data–not necessarily tied to indviduals but maybe by region?

The table on the page you are referencing explains how the INDNAICS codes relate to the IND codes in IPUMS USA. This is a full list of all NAICS codes available in the ACS, however in principle full detail of all NAICS categories is restricted due to confidentiality restrictions on public use data. Basically, the more people that identify a given industry, the more detailed industry codes can be within that industry. See theCensus Bureau’s documentation for more information. An additional industry coding scheme, available in IPUMS USA, can be found in the IND variable. Both of these coding schemes have similar levels of detail.