The acronym MECE is widely used in management and stands for Mutually Exclusive and Collectively Exhaustive. Its a quality that a proposed set of categories may or may not have.
If categories are ‘mutually exclusive’ then no item can belong in more than one category
If categories are ‘collectively exhaustive’ then all items are in at least one category.
For many forms of problem solving it is necessary to arrange data into MECE categories to avoid double-counting and other misrepresentations.
( Add examples – cake vs cheese)
( Adapt Magnus’ example of car parts – note that comfort and safety are not orthogonal — eg shock absorbers)
Mathematicians will note that MECE is essentially the same concept they know as Complete and Exhaustive, typically applied to coordinate systems, Fourier analysis etc.