What is a pre-mortem? A pre-mortem is a planning exercise where you imagine a project has already failed, then write down every reason why. It reverses the usual post-mortem, which looks at failure after it happens. Psychologist Gary Klein popularized it in a 2007 Harvard Business Review article. A pre-mortem helps teams spot risks early, while the plan can still change.
Last updated: October 15, 2026. Written by the Crowd Before team.
Run a pre-mortem on your idea with Crowd Before
Key facts
- Inventor: Gary Klein, a research psychologist, described the method in the September 2007 Harvard Business Review article "Performing a Project Premortem."
- Core idea: imagine the project failed, then explain why. This is called prospective hindsight.
- Time needed: as little as 20 to 30 minutes for a team, according to Klein.
- Evidence base: a 1989 study by Mitchell, Russo and Pennington on prospective hindsight, and later work on overconfidence. The evidence is real but limited.
- Best used: before you commit time or money, not after.
- Related data: CB Insights' March 2026 review of 431 VC-backed shutdowns found 43% cited poor product-market fit, a risk a pre-mortem can surface early.
Pre-mortem definition
A pre-mortem (also written premortem) is a structured exercise in which a team assumes a plan has failed and works backward to explain the failure. Instead of asking "what could go wrong?", the team states "it went wrong, so what happened?"
That small change in wording matters. People find it easier and safer to explain a failure that has "already happened" than to criticize a plan they are about to launch.
Pre-mortem vs post-mortem
| Pre-mortem | Post-mortem | |
|---|---|---|
| When | Before the project starts or ships | After the project ends |
| Question | "It failed. Why?" | "It failed. What happened?" |
| Purpose | Fix the plan now | Learn for next time |
| Cost of changes | Low | The damage is done |
Why does a pre-mortem work?
Planning teams tend to be overconfident, and people often stay quiet about doubts to avoid looking negative. A pre-mortem makes risk-spotting the goal, so raising concerns becomes helpful instead of disloyal.
The research behind it is often summarized as prospective hindsight increasing the ability to identify reasons for future outcomes by 30%. Be careful with that figure. Reviewers of the original 1989 study note it measured roughly 30% more reasons generated, not 30% more accurate reasons. The method is useful and widely used, but the strongest honest claim is that it helps people think of more ways a plan could fail.
How to run a pre-mortem: 6 steps
- Prepare. Everyone understands the plan, the goal and the deadline.
- Picture the failure. Announce: "It is one year from now. The project failed badly."
- Generate reasons. Each person writes down every reason for the failure, alone and in silence, for a few minutes.
- Share. Go around the room and collect one reason at a time into a single list.
- Rank. Pick the reasons that are both plausible and serious enough to sink the project.
- Revise the plan. Add safeguards, tests or a new approach for each top risk. Revisit the list every few weeks.
Klein also described a "double-barreled" version: after imagining failure, imagine huge success and ask what could go wrong there too.
A startup pre-mortem template
Use this if you are a solo founder or a small team. Write the failure story first:
"It is 12 months from now. We launched [idea] for [customer] at [price]. Almost nobody is paying. Why?"
Then answer these prompts:
| Risk area | Prompt | Test before building |
|---|---|---|
| Problem | Did we misjudge how painful the problem is? | Interview 8 to 10 target customers |
| Customer | Did we pick the wrong segment? | Compare segments, narrow the audience |
| Solution | Did people prefer their current workaround? | Concierge or prototype test |
| Price | Was the price too high, or too low to be taken seriously? | Pricing page test, pre-sale |
| Competition | Did a competitor do it better or cheaper? | Competitor and review analysis |
| Reach | Could we not find buyers affordably? | Test one channel with a small budget |
| Money | Did the economics not work? | Rough break-even model |
| Timing | Was it too early or too late? | Trend and urgency check |
| Team | Did we run out of time or energy? | Set a scope and decision date |
Rank the top three. Those are the assumptions to test first.
Pre-mortem examples
Example 1: a booking app for pet sitters. Failure story: "Nobody used it." Reasons: owners already use friends and neighbors, trust is hard to build, sitters list on three other sites. Safeguard: interview 10 owners about how they find sitters today before building.
Example 2: a B2B scheduling tool. Failure story: "Clinics did not switch." Reasons: switching cost is high, the front-desk team resisted, an existing tool added the feature. Safeguard: run a paid pilot with two clinics and track whether they keep using it.
These are illustrative scenarios, not real companies.
Pre-mortem vs other risk tools
| Tool | What it does | How it differs |
|---|---|---|
| SWOT analysis | Lists strengths, weaknesses, opportunities, threats | Static list. Does not assume failure. |
| Risk register | Tracks known risks, likelihood and impact | Useful later. Pre-mortem finds risks first. |
| Post-mortem | Reviews a failed project | Happens after the damage. |
| Customer interviews | Learn from real buyers | Evidence, not brainstorming. Use both. |
| Crowd test | Shows how a target market might react | Adds outside reactions to your own guesses. |
The limit of a pre-mortem
A pre-mortem only surfaces risks you and your team can imagine. If your whole team shares the same blind spot, you will miss it. That is why founders should combine it with outside reactions, such as customer conversations and a crowd test.
Pre-mortem for startups with Crowd Before
Crowd Before works like a pre-mortem with outside voices. Its hero line says it plainly: find out why your idea fails, before you build it. You describe your idea and price and pick a market. It puts the idea in front of 100 to 5,000 AI-generated buyers shaped by real demographic, income and industry data, then 12 of them debate it.
Your report shows where buyers drop off (have the problem, hit it often, want a fix, would pay), the top objections with fixes, real competitors from the web and a verdict: Build it, Rethink it, or Don't build this yet. The objections are a ready-made list of failure reasons to feed your own pre-mortem. Watch a sample run to see one, or read how it works.
The crowd is AI-generated, so the objections are hypotheses to check with real customers, not proof. Your first idea is free.
Find out why your idea might fail
Who should run a pre-mortem?
- Founders about to build or launch
- Teams planning a new feature or campaign
- Product managers weighing a big bet
- Anyone choosing between several ideas
Need an idea to stress-test? Use the free idea generator. Want other founders to poke holes in yours? Post it in the community.
FAQ
What is a pre-mortem in simple terms?
You imagine your project has failed and list the reasons why. Then you fix the plan to avoid them.
Who invented the pre-mortem?
Gary Klein, a research psychologist, who described it in a 2007 Harvard Business Review article.
How long does a pre-mortem take?
A team can do one in 20 to 30 minutes. A solo founder can do a useful one in about 15 minutes.
What is the difference between a pre-mortem and a post-mortem?
A pre-mortem happens before a project and aims to prevent failure. A post-mortem happens after and aims to learn from it.
Does a pre-mortem really work?
It helps people think of more risks and speak up about doubts. The evidence base is limited, so use it alongside real customer evidence.
Can a solo founder do a pre-mortem?
Yes. Write the failure story, set a timer, list every reason, and rank the top three. Then ask a friend or a founder community to add reasons you missed.
How do I do a pre-mortem on a business idea?
Imagine the idea failed in a year, list reasons by problem, customer, price, competition, reach and money, then test the top risks with interviews, a crowd test and a paid demand test.
What should I do after a pre-mortem?
Turn each top risk into a test or a change to the plan. A list with no action does not help.
Sources
- Klein, G. "Performing a Project Premortem," Harvard Business Review, September 2007
- Mitchell, Russo and Pennington (1989), study on prospective hindsight, as summarized by Klein
- CB Insights, startup failure reasons (March 2026)
Next steps
Read why startups fail in 2026 for the data behind the common risks, or how to test a business idea before building for the full process.