Goodhart's Law
Juking the Stats
When a measure becomes a target, it ceases to be a good measure. People optimize for the metric itself rather than the outcome it was meant to track.
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Origin
British economist Charles Goodhart first articulated the principle in a 1975 paper written during his time at the Bank of England. Marilyn Strathern later generalized it in 1997 to the now-famous phrasing: "When a measure becomes a target, it ceases to be a good measure."
Updated February 22, 2026