When a Graph Is a Matter of Life and Death

(p. 72) In her authoritative book The Challenger Launch Decision, sociologist Diane Vaughan demolishes the myth that NASA managers ignored unassailable data and launched a mission absolutely known to be unsafe. In fact, the conversations on the evening before launch reflected the confusion and shifting views of the participants. At one point, a NASA manager blurted, “My God, Thiokol, when do you want me to launch, next April?” But at another point on the same evening, NASA managers expressed reservations about the launch; a lead NASA engineer pleaded with his people not to let him make a mistake and stated, “I will not agree to launch against the contractor’s recommendation.” The deliberations lasted for nearly three hours. If the data had been clear, would they have needed a three-hour discussion? Data analyst extraordinaire Edward Tufte shows in his book Visual Explanations that if the engineers had plotted the data points in a compelling graphic, they might have seen a clear trend line: every launch below 66 degrees showed evidence of (p. 73) O-ring damage. But no one laid out the data in a clear and convincing visual manner, and the trend toward increased danger in colder temperatures remained obscured throughout the late-night teleconference debate. Summing up, the O-Ring Task Force chair noted, “We just didn’t have enough conclusive data to convince anyone.”

Collins, Jim. How the Mighty Fall: And Why Some Companies Never Give In. New York: HarperCollins Publishers, Inc., 2009.
(Note: italics in original.)

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