The McNamara Fallacy

During the Vietnam War, Defense Secretary Robert McNamara measured success by body counts — enemy killed per week. The numbers looked excellent. America was "winning" statistically while losing the war in every way that mattered.

The McNamara Fallacy has four steps: measure what is easy to measure, disregard what cannot be measured, presume what cannot be measured is not important, then presume it does not exist.

Organizations repeat this constantly. Schools measure test scores, not curiosity. Hospitals measure throughput, not health outcomes.