PreMortem Exercise
The PreMortem Exercise is a technique for discovering critical flaws in a plan, by pretending that a plan failed and then trying to perform a list the reasons why it could have failed, then performing a post-mortem analysis on those theoretical failure causes. It was developed as part of the Decision Making Games for the U.S. Marine Corps by Gary Klein and colleagues.
How a PreMortem can help product development
By imagining that a plan has already failed, participants step outside their usual perspective and think more critically about potential weaknesses. This shift in framing helps uncover flaws that might otherwise be overlooked during optimistic planning. The exercise also creates a safe environment for raising concerns, since participants are explaining a hypothetical failure rather than criticising a proposed approach. Addressing the identified concerns typically leads to a stronger plan.
The PreMortem technique seems to significantly reduce overconfidence, and seems to do a better job at that than other comparable techniques.
Gary Klein, Success Through Failure: The PreMortem Method
Origins of the PreMortem Exercise
In Linking Expertise and Naturalistic Decision Making, the authors suggest to ask the group to consider that, “by looking into a crystal ball it is determined that the plan failed”, based on the Crystal Ball method proposed by Cohen, Freeman And Thompson.
In Performing a Project Premortem, Klein proposes a doing the Premortem as part of a project kick-off, once everyone knows the plan and what their role is in the plan. The exercise should take between 20 minutes and a half-hour.
- First, the facilitator asks people to lean back, relax, and says that they have “looked into an imaginary crystal ball” (in Success Through Failure: The PreMortem Method, Klein even suggested bringing along an actual crystal ball), and that six months or a year after the project started it failed, “it was a disaster, a fiasco, the people on the team when they pass each other avoid eye contact because it’s so painful”
- Individual group members then need to spend a bit of time independently writing all the reasons why that could have happened. Klein suggests spending a very short amount time on this, no more than a few minutes.
- The facilitator then records all the reasons on a shared writing space (whiteboard or a virtual board). Each person puts up one idea that was not already covered, starting from the most senior participant (“project leader”).
- Once the team has discussed the potential problems, the facilitator starts a “backup exercise”, asking people to write down what they could do individually to prevent or reduce the effects of the listed issues (again limited to only a few minutes).
- The project leader can then look for ways to strengthen the plan.
Presenting the crystal ball as infallible changes people’s mindsets, and takes the pressure off from trying to make a plan work to actually discovering flaws. Asking individuals to put forward ideas that were not proposed by other people before them also stimulates creativity. Instead of being afraid that criticisms will “disrupt the harmony of the team”, people end up “competing with each other to come up with plausible problems that have not been discussed yet”.
In Success Through Failure: The PreMortem Method Klein suggests doing the initial problem collection and the backup exercise in about two minutes each. Limiting it to one minute seemed to catch people unprepared and lots of participants were still writing when the time was up. Extending it to longer caused people to “run out of steam”.
Asking the project leader of the project manager to speak first opens up a “culture of candor”, as people will not be afraid to say what’s unpopular. The project leader sets the tone by speaking first, and shows they are willing to take the risk that the plan is wrong.