Operating Principle
2–4 min read
The MUM effect describes a robust reluctance to deliver bad news, intensified by power differences. Each organizational layer filters and softens negative information on its way up, so consequential decisions are made on data that is systematically more optimistic than reality.
Operating Question
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Why It Matters
People are reluctant to deliver unwelcome news upward, leaving leaders structurally last to learn what is wrong.
Supporting Evidence
Rosen and Tesser on the MUM effect; Morrison and Milliken on organizational silence.
Research Notes
Treat this as an operating heuristic and weigh the relevant context and limitations.
Practical Actions
Create a specific ritual for surfacing bad news early; reward the first messenger; ask directly for the worst news.