Classification

Having mentioned Dewey, LCC and the USGS classifications recently it seemed to be a good time to mention a few classification schemes. The American Physical Society publishes The Physics and Astronomy Classification Scheme.

"This Classification Scheme, on the other hand, is arranged hierarchically, by subdivision of the whole spectrum of subject matter in physics- and astronomy-related sciences into segments and then repeating the process of subdivision down to four levels. The advantages of a hierarchical scheme over the alphabetical arrangement include: like subjects can be found grouped closely together; and browsing up or down near any entry will reveal closely-related entries."

For Math, there is the Mathematics Subject Classification from the American Mathematical Society.

"(MSC) is used to categorize items covered by the two reviewing databases, Mathematical Reviews (MR) and Zentralblatt MATH (Zbl). The MSC is broken down into over 5,000 two-, three-, and five-digit classifications, each corresponding to a discipline of mathematics."

"The North American Industry Classification System (NAICS) has replaced the U.S. Standard Industrial Classification (SIC) system. NAICS will reshape the way we view our changing economy.

NAICS was developed jointly by the U.S., Canada, and Mexico to provide new comparability in statistics about business activity across North America."