What are NAICS and PSC codes & how they’re organized

The government loves codes, every agency has a code, every type of work has a code, every company has a code, and you don’t need to know much about the history or structure of PSC and NAICS codes but here are a couple things to be aware of:

North American Industry Classification System (NAICS) Codes:
In theory NAICS codes provide a unique code for every industry out there. So there’s a code for legal services and there’s a code for Truck Repair and everything in between. The system starts at two digits (general industries), and goes to six digits (very specific industries). For example NAICS code:
-11:  Agriculture, Forestry, Fishing and Hunting (Very general)
-111: Crop Production
-1113: Fruit and Tree Nut Farming
-11133: Noncitrus Fruit and Tree Nut Farming
-111331: Apple Orchard

Product and Services (PSC) codes:
In theory PSC codes  provide a unique code for every product or service.  PSC codes can be up to four characters and are composed of numbers and letters.  Like with NAICS codes, the longer PSC code the more detailed the product or service. For example PSC code:
-R: Support Services (Prof, Admin, Mgmt)
-R7: Management Support Services
-R701: Advertising Services

One helpful thing to know about PSC codes is that the first character tells you a lot.  If the first character is:
1) A number (e.g. 1 or 7): Then the code is for a product
2) An “A:” Then the code is for R&D services
3) Any other letter (e.g. B or W): Then the code is for another service