I think it would be foolish to try and replace the NAICS system. NAICS is the federal government's categorization system, and in my experience, it is also in use at the municipal level in the United States. Here's a longer description:
NAICS was developed under the auspices of the Office of Management and Budget (OMB), and adopted in 1997 to replace the Standard Industrial Classification (SIC) system. It was developed jointly by the U.S. Economic Classification Policy Committee (ECPC), Statistics Canada , and Mexico's Instituto Nacional de Estadistica y Geografia , to allow for a high level of comparability in business statistics among the North American countries.
It's easy to hate on a system that only gets as specific as "Custom computer programming services", but in reality, it was developed with a lot of effort by a bunch of smart folks.
In my opinion, there are two challenges when trying to compare prices across governments:
- NAICS is not always specific enough, especially when it comes to technology.
- Units are not standardized.
While I would love to see a data standard that fixes these issues, think it's inevitable that there is always going to be a large amount of discretion/manual comparison involved. Because of this, I'd be much more interested in a system that allows a user to view aggregated pricing data from multiple cities, filtered by query or NAICS code. It would pull from multiple sources like the City of Chicago link in the original post.
As far as NAICS goes -- maybe we could create additional subcategories for codes that are way too broad, such as "Custom computer programming services"? Or taking this idea further, would there be a way to create a superset of NAICS that extends it so it never goes out of date?
EDIT: There's a discussion going on about this at https://github.com/dobtco/NAICS/issues/1