Gary Klein described the method in Harvard Business Review in 2007. “A premortem is the hypothetical opposite of a postmortem.” Instead of asking what might go wrong, the leader tells the team the project “has failed spectacularly” and asks why Published.

How it runs

1. Brief the planEveryone hears the final version, including the kill criteria.
2. Announce the failure“It’s six months from now. This launch failed badly.” Make it certain, not possible.
3. Write aloneEach person spends a few minutes writing every reason they can think of, “especially the kinds of things they ordinarily wouldn’t mention,” in Klein’s words.
4. Go around the roomOne reason per person per turn, starting with the project lead, until every reason is on the list.
5. Change the planThe project lead reviews the list and strengthens the plan. Anything that can’t be fixed becomes a kill criterion or a signal to watch.

PublishedKlein, “Performing a Project Premortem,” Harvard Business Review, September 2007.

What the research found, accurately

Klein’s article cites a 1989 study by Deborah Mitchell, Jay Russo and Nancy Pennington, and says it found that imagining an event has already happened “increases the ability to correctly identify reasons for future outcomes by 30%” Published. That’s not quite what the study measured. It counted reasons, not correct ones. People told an outcome was certain gave longer explanations, more tied to specific events, than people told it was only possible; a 2010 paper co-written by Klein summarized the effect as about 30% more reasons Published. The 1989 paper’s own abstract adds that certainty, not setting the event in the future or the past, drove the difference. The quoted figure is about quantity, not accuracy.

Later tests are small but encouraging. In that 2010 study, by Beth Veinott, Klein and Sterling Wiggins, with 178 students judging a flu-response plan, groups that ran a premortem lowered their confidence in it by 25 points on average, against 12 to 14 points for groups that listed pros and cons or only cons Published. More reasons and less overconfidence is what a launch plan needs. Treat it as a cheap habit with a sound mechanism, not a proven 30% gain.

Certainty loosens tongues. “It failed” gets more honest answers than “could it fail?”

Making it work in a small team

• Include the people closest to the work: customer service, the 3PL contact, the designer. They know the failure modes the plan doesn’t.
• The founder writes too, and speaks last. Otherwise the list becomes the founder’s list.
• Keep the list. It goes in the decision journal, and at the review you’ll see which failures you predicted.

Do this

• Book twenty minutes before your next launch, promotion or channel test. Run the five steps, and change at least one thing in the plan because of what comes out. If nothing changes, you ran it too politely.