MECE Framework

Use this skill to check and improve whether a structure is clear, non-overlapping, and complete enough for decision work.

Method Notes

• MECE means Mutually Exclusive and Collectively Exhaustive.
• Mutually exclusive means categories do not overlap in a way that creates double counting or unclear ownership.
• Collectively exhaustive means the structure covers all material parts of the question within the chosen scope.
• MECE is a discipline, not a slogan. Use it to improve clarity, not to make every real-world situation artificially neat.

Required Inputs

Collect or infer these inputs before execution:

• core question or decision
• current structure, list, tree, segmentation, options, hypotheses, or workplan
• scope boundary
• intended use of the structure
• known exclusions, constraints, or edge cases

If an input is missing, do not block automatically. Mark it as missing, state the assumption used, and add a validation action.

When Not To Use

Do not use MECE when the user is still exploring raw ideas and premature structure would hide weak signals. Use affinity-diagram or mind-map-analysis first.

Step-by-Step Execution

Output Template

### 1. Scope
- Core question:
- Structure being tested:
- In scope:
- Out of scope:

### 2. Current Structure
| Branch / item | Current definition | Level | Issue detected |
|---|---|---|---|
|  |  | same level / mixed level | overlap / gap / unclear / ok |

### 3. MECE Diagnosis
| Problem | Where it appears | Why it matters | Fix |
|---|---|---|---|
| overlap / duplicate / mixed level / missing branch / unclear boundary |  |  |  |

### 4. Revised MECE Structure
| Branch | Inclusion rule | Exclusion rule | Example items |
|---|---|---|---|
|  |  |  |  |

### 5. Stress Test
- Item that fits clearly:
- Edge case:
- Remaining ambiguity:
- Next refinement:

Quality Gate

• Do not confuse MECE with excessive completeness. The structure only needs to be complete for the current decision scope.
• Keep items at the same logical level whenever possible.
• Avoid mixing causes, symptoms, actions, owners, and metrics in the same branch set unless that is the deliberate design.
• Define inclusion and exclusion rules for ambiguous branches.
• If full MECE is impossible, state the practical boundary and remaining ambiguity.