Goodharts Law: When Metrics Become Targets They Stop Working

The Metric Trap

"When a measure becomes a target, it ceases to be a good measure." This explains why well-intentioned measurement programs produce perverse outcomes.

Classic Examples

Soviet nail factories: Measured by number, they made tiny useless nails. Measured by weight, enormous ones.

Call centers: Measured by calls/hour, agents rush customers. Satisfaction plummets.

Lines of code: Measured by LOC, developers write verbose, unmaintainable code.

These are rational responses to misaligned incentives.

Solutions

1. Balanced scorecards: Multiple metrics that check each other
2. Rotate metrics: Periodically change what you measure
3. Pair metrics: For every efficiency metric, add a quality metric
4. Measure outcomes, not activities: Focus on what matters to users
5. Qualitative assessment: Some things cannot be reduced to numbers

The decision masters understand: any single metric can be gamed, but a portfolio of metrics is harder to game.

Learn more at KeepRule. Practice with decision scenarios.

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Measure wisely. KeepRule