A premortem is Gary Klein's procedure, endorsed by Kahneman: before committing to a plan, imagine it failed catastrophically, then write the history of how that failure happened. Legitimizes dissent and surfaces risks the group's optimism suppressed.
Why it works
Planning meetings reward confidence; premortem gives cover to skeptics. It fights planning-fallacy, wysiati, and organizational lethargy when bad reference-class data is noted then ignored.
Complements reference class forecasting and checklists — organizations think more slowly and can impose orderly procedures humans resist individually.