Is there some generally academic accepted categorization of subject areas and subject categories?
Australia and New Zealand rely upon the Australian and New Zealand Standard Research Classification (ANZSRC).  This standard comprises of Type of Activity (TOA); Fields of Research (FOR); and Socio-economic Objective (SEO).

You would be most interested in the Fields of Research code specifications.  In the FOR code, Division 08 Information and Computing Sciences includes group 0806 Information Systems which is specified here: http://www.abs.gov.au/Ausstats/abs@.nsf/Latestproducts/21AF3378B57615E7CA25741800047563?opendocument

Sources:


http://www.arc.gov.au/applicants/codes.htm#ANZSRC
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