Pre-Mortem

How it works

Psychologist Gary Klein developed the pre-mortem as an antidote to two common problems: optimism bias (we tend to overestimate our chances of success) and groupthink (teams suppress dissent, especially after a plan has been agreed upon).

The technique works by giving people explicit permission to think about failure. In a standard post-mortem, you examine what went wrong after the fact. In a pre-mortem, you do it before — when you can still change course.

The process has four steps. First, gather your team or sit alone with your plan. Second, announce: “Imagine it’s six months from now. This project has failed completely. It’s a disaster.” Third, everyone independently writes down all the reasons why it failed. Fourth, share the lists and identify the most likely and most preventable failure modes. Then update your plan to address them.

Case study: How NASA’s pre-mortem culture prevented Apollo 13 from becoming a tragedy

On April 13, 1970, an oxygen tank exploded aboard Apollo 13, crippling the spacecraft 200,000 miles from Earth. What could have been the worst disaster in spaceflight history became instead what NASA calls its “successful failure.”

The reason Apollo 13’s crew survived was that NASA’s Mission Control had spent years running pre-mortems — they called them “failure mode analyses.” For every conceivable system failure, they had already asked: “If this breaks, what do we do?” They had procedures for scenarios most people would never imagine: using the lunar module as a lifeboat, improvising CO2 scrubbers from materials on board, and navigating without a computer.

When the real crisis hit, the response team wasn’t inventing solutions from scratch. They were executing plans that had been refined through hundreds of imagined failures. The pre-mortem culture didn’t prevent the crisis — but it made the difference between catastrophe and survival.

Real-world examples

Product launches. Before shipping a new feature, a team runs a pre-mortem. They discover that the most commonly imagined failure mode isn’t technical — it’s that users can’t find the feature because the onboarding flow doesn’t mention it. This insight redirects effort from engineering polish to user experience, preventing a real failure.

Career moves. Before accepting a new job, imagine it’s a year later and you deeply regret the move. Why? Maybe the company culture clashed with your values. Maybe the role was misrepresented. Maybe the city was isolating. Now you know exactly what to investigate before signing.

When to use it

Run a pre-mortem before any important project launch, career decision, investment, or strategic commitment. It’s especially valuable in team settings where optimism bias and groupthink are strong — the pre-mortem format gives people social permission to voice concerns they’d otherwise keep quiet.

Common mistakes

The main mistake is treating it as a pessimism exercise rather than a planning tool. The point isn’t to kill the project — it’s to strengthen it. The second mistake is identifying risks but not assigning owners and mitigation plans. A pre-mortem without follow-up action is just worry with extra steps.

Try it now

Think of something you’re planning in the next month — a project, a trip, a presentation, a difficult conversation. Now imagine it went terribly. Write down three specific reasons why it failed. For each one, ask: “What could I do this week to make that failure less likely?”

Related models

These models complement Pre-Mortem — they address similar situations from different angles.