McNamara fallacy

Uncommon card · No. 161573

The McNamara fallacy (also known as the quantitative fallacy), named for Robert McNamara, the U.S. Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations (or metrics) and ignoring all others. The reason given is often that these other observations cannot be proven. Here is what happens when the McNamara discipline is applied too literally: The first step is to measure whatever can be easily measured. This is okay as far as it goes. The second step is to disregard that which can't be easily measured or give it an arbitrary quantitative value. This is artificial and misleading. The third step is to presume that what can't be measured easily really isn't very important. This is blindness. The fourth step is to say that what can't be easily measured really doesn't exist. This is suicide. Yankelovich believed that this approach was what led the United States to defeat in the Vietnam War—specifically, McNamara's focus on quantifiable measures...

Read on Wikipedia