The premortem
Before kicking off a project, imagine it failed. Write the obituary.
A premortem is a planning exercise developed by Gary Klein, a psychologist who studied how experienced experts (firefighters, military commanders, ER doctors) actually make decisions under pressure.
The mechanic is simple. Before you start a project, gather the team and tell them: "Imagine it's one year from now. The project failed, badly. Spend 5 minutes writing down what happened." Then go around the room and read what people wrote.
This sounds like a small thing. It's actually one of the highest-ROI planning exercises a team can do, for two reasons.
First, it changes what people are allowed to say. In a normal kickoff, asking "what could go wrong?" produces bland answers ("the timeline is aggressive"). It feels disloyal to predict failure. The premortem reframes the room: failure is the given, you're just diagnosing why. People mention things they would never have voiced in the optimistic version.
Second, it reverses the default bias. Most planning runs in success mode (how do we win?). Premortems run in failure mode (how did we lose?). Failure modes are easier to spot when you start from failure as a fact, not a hypothetical.
Daniel Kahneman has endorsed the premortem publicly as one of the few simple interventions that reliably improves decision quality.
How to run one well:
1. Do it before the project starts, not after the strategy is set in stone. The point is to change the plan, not to feel clever. 2. Have everyone write silently first, then read out. Otherwise the senior person's opinion shapes the room. 3. Cluster the failure modes after. Some of them will be the same thing said five different ways. The clustering tells you which risks are real. 4. For each big cluster, decide what you'll do now to prevent or mitigate it.
A small caveat. Premortems work less well if the team isn't honest. If pessimism is culturally punished, no one will write down what they actually think will go wrong. The exercise is only as good as the safety of the room.
Examples in the wild
Daniel Kahneman recommends premortems as a 30-minute exercise that catches failure modes worth months of project pain. Cost: half a meeting. Return: a few risks you would have hit blindly.
Before a major investment, write the failure version: 'It's 3 years later, the investment lost half its value, why?' The answers often reveal risks the optimistic version concealed. Howard Marks essentially does this in every memo.
Before a difficult conversation, do a 5-minute premortem: 'Imagine this conversation went badly. What did I say that made it worse?' You catch tone problems before they happen.
The premortem is one of the mental models we apply through real cases inside the Pareto MBA — a part-time program for professionals who want to think clearly about business.