Decompose classification into independent facets when items…
Decompose classification into independent facets when items genuinely belong to multiple categories simultaneously, rather than forcing single-parent assignment.
Why This Is a Principle
Derives from Schemas as Knowledge Organization Structures (schemas specify relationships) and Flexible Context-Dependent Categorization (conceptual structure organizes along multiple dimensions). This is Ranganathan's faceted classification as a design principle: use multiple independent dimensions when items have legitimate multi-dimensional membership. Prescriptive, actionable, addresses polyhierarchy.
Source Lessons
Multiple valid hierarchies for the same data
The same set of items can often be organized in several equally valid hierarchical structures. Each hierarchy foregrounds different relationships and obscures others. No single arrangement is canonical — the right hierarchy depends on what you are trying to see, find, or do. Recognizing this multiplicity is a precondition for deliberate knowledge design.
Boundary cases test your categories
Items that do not fit neatly into any category expose weaknesses in your system.