The art of thinking · Mental models as thinking tools
Pre-mortem
Also known as: Premortem, Project premortem, Prospective hindsight
A pre-mortem is a decision technique described by the psychologist Gary Klein in which a team, before a plan is carried out, imagines that it has already failed and writes down every reason why — using prospective hindsight to surface risks that optimism and group pressure hide.
- Thinking models
- Problem solving
- Strategy
In one sentence
In a pre-mortem a team imagines its plan has already failed and lists why — Gary Klein’s use of prospective hindsight.
Example
Before the new online help goes live, the team writes: “Six months later, the service hotline gets more calls than before. Why?” The answers — search doesn’t know field terms, PDFs disappeared — become tasks before launch.
How it applies
- The procedure: The team is told the project has failed spectacularly; everyone writes down independently the reasons; the reasons are collected, discussed and turned into changes of the plan.
- Why it works: Mitchell, Russo and Pennington (1989) found that imagining an event as having already happened increased the number of reasons people generated for its outcome — the effect called prospective hindsight. The pre-mortem also makes it legitimate to voice doubts.
- Evidence status: The technique is widely used and supported by research on prospective hindsight and on reducing overconfidence; controlled studies of the full technique are fewer than its popularity suggests.
- Technical documentation: Pre-mortems suit documentation projects — a new portal, a restructured manual, a translation workflow. For product risks they are a brainstorming aid; they never replace the systematic risk assessment of the product.
Pre-mortem vs. post-mortem
A post-mortem explains a failure that happened; a pre-mortem uses the same questions before anything has failed, when the plan can still change.
How to read this pool
Entries, context cards and transitional topics
The art of thinking explains ways of thinking — where a method comes from, what it asks of you and how it was adapted later. You meet four kinds of content here, each with its own job:
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