Mutually Exclusive & Comprehensively Exhaustive. It's how to do bullet points according to McKinsey. They had to invent it in the 1960s because apparently by the 1960s no one at McKinsey was yet, you know, aware of the existence of centuries' worth of literature on formal logic. So they reinvented the wheel as far as that particular cultural achievement was concerened. Or the first millionth of it, to be more precise, and left it at that, because the rest of it would have no longer fit onto a single PowerPoint slide.
Alternatively, this is just some guy asserting that everyone at McKinsey thinks they invented a brand new concept, when in fact, it’s just a heuristic they teach people to communicate more effectively, because communication is hard.
Edit: I cannot reply to the below, but I will say, that’s a pretty contrived justification for your view.
Communication is hard. Few things done at a corporate scale are easy to implement. People like to point at big consulting firms and say “I could have done that” or “they could have just asked me” but that’s really just a fraction of it.
Mango-eating computer engineers?
No, that doesn't fit in based on the context clues...