What’s the Point of a Post-Mortem?
What’s the Point of a Post-Mortem? The purpose of a post-mortem is not simply to explain what went wrong. It is to reconstruct what people expected, determine why reality differed, identify the conditions that shaped the outcome, and make specific changes that improve future decisions. Organizations often conduct reviews after failures, outages, missed deadlines, and unsuccessful launches. The resulting documents can contain detailed timelines and accurate descriptions without producing much learning. The problem is that explanation and improvement are different outcomes. A post-mortem becomes useful when it changes how people understand the system and what they do afterward. The Obvious Cause May Not Be the Useful Cause On February 28, 2017, Amazon Web Services experienced a major disruption to its S3 service in Northern Virginia. An authorized employee investigating a billing-system problem entered an incorrect input into an operational command. The command removed far more server ca...