The Tyranny of Metrics · Jerry Z. Muller

Goodhart's law examples

Curated by · reviewed 2026-05-31

Goodhart's law says that when a measure becomes a target, it stops being a good measure — people optimise the number instead of the thing it was meant to track. Examples:

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5 examples of goodhart's law

  1. Teaching to the test

    Grade schools on test scores and they drill the test — scores rise while real learning doesn't.

  2. Call quotas

    Reward the number of sales calls and reps make many short, useless calls just to hit the count.

  3. Lines of code

    Pay developers by lines written and you get bloated, padded code instead of good software.

  4. Wait-time targets

    Hard targets on hospital wait times can get gamed (holding patients elsewhere) rather than producing faster care.

  5. Vanity metrics

    Chase likes or sign-ups as the goal and people optimise for cheap likes and empty sign-ups, not real value.

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