Definition
Once a metric is treated as the goal, people optimise the metric — often at the expense of the underlying capacity the metric was meant to indicate.
Origin
Named after economist Charles Goodhart’s observation on monetary targets (1984 chapter). Later popularised beyond economics (often via Marilyn Strathern’s phrasing) as a general warning about targets in organisations, education, and personal dashboards.
Mechanism
A useful indicator becomes a target. Agents then change behaviour to move the number. The correlation between the number and the real outcome weakens or reverses. Classic pair: watch vanity metrics (likes, comments) while under-executing the lead behaviours (publish, practice, recovery reps) that produce the intended result.
Applications
- Prefer lead behaviours you can train today over outcome scores you only notice when they fail.
- When reviewing a week, ask: Which measures did I optimise that left the gap between intention and execution untouched?
- Use as a diagnostic beside Lag vs Lead Measure — not as an excuse to abandon measurement.
Sources
Cite
- Goodhart, C. A. E. (1984). Problems of monetary management in the United Kingdom. In P. M. Jackson (Ed.), Monetary theory and practice (pp. 91–121). Macmillan.
- Strathern, M. (1997). ‘Improving ratings’: audit in the British University system. European Review, 5(3), 305–321.