Maybe it’s because it’s because I just finished reading this section in Range, but I think it’s more than the engineers knew.

When sociologist Diane Vaughan interviewed NASA and Thiokol engineers who had worked on the rocket boosters, she found that NASA’s own famous can-do culture manifested as a belief that everything would be fine because “we followed every procedure”; because “the [flight readiness review] process is aggressive and adversarial”; because “we went by the book.” NASA’s tools were its familiar procedures. The rules had always worked before. But with Challenger they were outside their usual bounds, where “can do” should have been swapped for what Weick calls a “make do” culture. They needed to improvise rather than throw out information that did not fit the established rubric.

Roger Boisjoly’s unquantifiable argument that the cold weather was “away from goodness” was considered an emotional argument in NASA culture. It was based on interpretation of a photograph. It did not conform to the usual quantitative standards, so it was deemed inadmissible evidence and disregarded. The can-do attitude among the rocket-booster group, Vaughan observed, “was grounded in conformity.” After the tragedy, it emerged that other engineers on the teleconference agreed with Boisjoly, but knew they could not muster quantitative arguments, so they remained silent. Their silence was taken as consent. As one engineer who was on the Challenger conference call later said, “If I feel like I don’t have data to back me up, the boss’s opinion is better than mine.”

I think most of us believe decisions should be data driven, but in some edge cases gut instinct is valuable.

It is easy to say in retrospect. A group of managers accustomed to dispositive technical information did not have any; engineers felt like they should not speak up without it. Decades later, an astronaut who flew on the space shuttle, both before and after Challenger, and then became NASA’s chief of safety and mission assurance, recounted what the “In God We Trust, All Others Bring Data” plaque had meant to him: “Between the lines it suggested that, ‘We’re not interested in your opinion on things. If you have data, we’ll listen, but your opinion is not requested here.’”