Problems with Premortems: Self-Serving Attribution Bias in a Popular Debiasing Strategy

Abstract

Before making major decisions, managers engage in prospective hindsight – imagining a future outcome and working backward from that outcome – to anticipate risks. The most popular type of prospective hindsight is the “premortem” – imagining a negative future outcome and identifying reasons why it occurred. Premortems have been broadly endorsed by psychologists and Nobel Prize winners as a debiasing strategy over the past two decades. However, surprisingly little research has investigated the premortem to identify whether or not it actually works. Across three studies that span prediction and planning domains, we find that the types of risks premortems identify are systematically biased. We contrast premortems, preparades, and preflections – imagining bad, good, or undefined outcomes – and find that individuals who engage in a premortem focus far more attention on factors outside of their control than do individuals who engage a preparade or preflection. Further, this effect persists across perspectives: individuals imagining self-relevant and other-relevant outcomes exhibit this bias. Together, our results suggest that although premortems mute overconfidence, they introduce attribution bias, ironically focusing managers’ attention away from the risks most within their control.