McNamara fallacy
The McNamara fallacy, named for Robert McNamara, the U.S. Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations and ignoring all others. The reason given is often that these other observations cannot be proven.
Daniel Yankelovich criticized McNamara's decision making as follows:
While Yankelovich originally referred to McNamara's ideology during the two months that he was president of Ford Motor Company, commentators have also discussed the McNamara fallacy in relation to his attitudes during the Vietnam War.
Examples in warfare
Vietnam War
The McNamara fallacy is often considered in the context of the Vietnam War, in which the U.S. Secretary of Defense Robert McNamara attempted to reduce war to a mathematical model.1962 meeting with Edward Lansdale
One example arose in an early 1962 conversation between U.S. Air Force Brigadier General Edward Lansdale and McNamara. Lansdale reportedly told McNamara, who was trying to develop a list of metrics to allow him to scientifically follow the progress of the war, that he needed to add an 'x-factor'; McNamara wrote that down on his list in pencil and asked what it was. Lansdale told him it was the feelings of the common rural Vietnamese people. McNamara then erased it and sarcastically told Lansdale that he could not measure it.1964 meetings with Desmond FitzGerald
New York Times correspondent David Halberstam wrote about McNamara's fixation on metrics:Body counts
Another example of the fallacy is the enemy body count metric which was taken to be a precise and objective measure of success. By increasing estimated enemy deaths and minimizing one's own, victory would be assured. Critics such as Jonathan Salem Baskin and Stanley Karnow noted that guerrilla warfare, widespread resistance, and inevitable inaccuracies in estimates of enemy casualties can thwart this formula.1965 Da Nang visit
David Halberstam wrote of another such incident in which qualitative facts were disregarded due to quantitative bias:Halberstam would conclude "...he did not serve himself nor the country well; he was, there is no kinder or gentler word for it, a fool."
Global war on terror
, US Secretary of Defense under George W. Bush, sought to prosecute wars with better data, clear objectives, and achievable goals. Writes Jon Krakauer:Although, Rumsfeld did show a sense of the existence, and importance, of data that was not quantifiable with his famous "There are unknown unknowns" answer to a question posed at a U.S. Department of Defense news briefing on February 12, 2002.
There are unknown unknowns|
This shows at least some progression away from the McNamara fallacy.