MECE Framework
Mutually Exclusive, Collectively Exhaustive problem structuring.
Explanation
This problem-structuring framework from McKinsey consulting ensures that when you break down a problem, your categories are Mutually Exclusive (no overlap) and Collectively Exhaustive (nothing is left out). This prevents you from double-counting things or missing important areas. If your analysis isn't MECE, your conclusions will be unreliable.
Real-World Example
Customer segments: 'New vs Returning' is MECE. 'Young vs Urban' is not (young urban people counted twice). Revenue breakdown: 'Product vs Services' is MECE. 'Online vs International' is not (overlap). Age groups: '0-17, 18-34, 35-54, 55+' is MECE. '0-20, 18-35, 30-50, 45+' is not.
How to Apply
Test ME: Can anything fit in multiple categories? If yes, redefine boundaries. Test CE: Is anything excluded? If yes, add categories. Common MECE: Yes/No, Before/During/After, Internal/External. Start broad (2-3 categories), then subdivide each. Document your logic—others need to understand your structure.