Why postmortems fail

Most high-profile disasters are followed by demands for an investigation into what went wrong. Even before they start, calls for finding the missed warning signs and an explanation for why people did not “connect the dots” will be common. Unfortunately, however, the same combination of political pressures and the failure to adopt good social science methods that contributed to the initial failure usually lead to postmortems that are badly flawed. The high stakes mean that powerful actors will have strong incentives to see that certain conclusions are—and are not—drawn. Most postmortems also are marred by strong psychological biases, especially the assumption that incorrect inferences must have been the product of wrong ways of thinking, premature cognitive closure, the naive use of hindsight, and the neglect of the comparative method. Given this experience, I predict that the forthcoming inquiries into the January 6, 2021, storming of the US Capitol and the abrupt end to the Afghan government will stumble in many ways.