I am a consultant and have seen many different classification schemes. They are all either by function or by department. The ones that are by function can usually be produced by department because that is how we produce the classification plan for each department to review, by maintaining an association between the department and the function.
I have never seen a classification plan by subject. Even the questions executives ask are by a criterion related to the documents within the records series. For example, they would ask a question by title rather than by person, or by product rather than by manufacturing process. Generally speaking, we eschew subject as much as possible even within departments where "subject files" have been renamed "reading files" for litigation purposes.
Records management classifications are a little less that 100 years old. Even then they were by function, the reason being--as it is now--that companies reorganize frequently, but they either eject an entire function or turn it over to another department.
There are additional criteria we use to distinguish one records series from another, such as privacy, sensitivity, or retention, but those are not so much facets as they are functional, i.e., mental health records are more sensitive than physical health records.
Hope this helps.
Carol E.B. Choksy, Ph.D., CRM
IRAD Strategic Consultant. Inc.
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