TWEGSLog inThe Pre-Mortem.
Before you commit, imagine the project has failed. Now work backwards to figure out why. It sounds morbid. It's the most honest hour you'll ever spend on a decision.
"Prospective hindsight — imagining that an event has already occurred — increases the ability to correctly identify reasons for future outcomes by 30%."
Mitchell, Russo & Pennington, 1989
Three cognitive tricks in one exercise.
The pre-mortem isn't just brainstorming risks. It's a purpose-built workaround for three biases that make us bad at predicting failure.
Defeats optimism bias
Once you're committed to a plan, your brain filters evidence that contradicts it. By treating failure as a fact, you get permission to see what was invisible.
Lowers social cost
It's career-limiting to raise doubts about the boss's pet project. But explaining why it already failed is just good storytelling — nobody gets defensive.
Uses prospective hindsight
Specifying a concrete outcome — "it failed" — triggers more detailed causal reasoning than abstract questions like "what could go wrong?"
Run your own pre-mortem.
Answer five prompts. We'll build a prioritized risk register with suggested mitigations. Takes about 10 minutes. Nothing leaves your browser.
Step 1 · The decision
Start by naming what you're about to commit to.
What exactly are you about to commit to?
Be specific. Include the who, what, and when. A vague decision yields vague failure modes.
[Action verb] [specific thing] by [date], committing [amount of money / time / reputation], expecting [specific outcome].
When to reach for it — and when not to.
The pre-mortem is overkill for reversible, low-stakes calls. Save it for decisions that hurt to unwind.
- The decision is hard or expensive to reverse (hiring, launches, acquisitions, contracts).
- A group is rallying behind a single plan and you sense premature consensus.
- You've been working on it for months and feel "too close" to see the cracks.
- The downside of failure is asymmetric — you can lose far more than you can gain.
- It's a two-way door — easily reversed with minimal cost.
- You need speed more than accuracy (the exercise itself takes 30+ min).
- The decision is routine and well-understood (hire #50 for a well-defined role).
- You've already run one recently on the same decision — diminishing returns kick in fast.
Gary Klein, 2007.
Research psychologist Gary Klein formalized the pre-mortem in a Harvard Business Review essay, drawing on decades of work studying how experts actually make decisions under pressure — firefighters, nurses, military commanders.
Daniel Kahneman later called it one of his favorite decision tools, writing that it's the single best antidote to the planning fallacy and groupthink he'd encountered in half a century of research.
"The prospective hindsight approach — imagining a failure has already happened — is a rare example of a psychological intervention that actually works in organizational settings."