From: Steve Holt
Sent: August 16, 2004
I'm reminded of a form of brainstorming I've
used for many years. I'd give credit to its source, but I can't remember where I got it!
It's called Plus-Minus-Interesting (PMI). The idea is that there are 3 phases to the
brainstorming session. In each phase the typical brainstorming rules apply (one idea per
person, complete sentences, etc.) but each phase has its own focus.
During Plus, only positive comments on the
topic are allowed. This has the effect of temporarily stopping both naysayers and devil's
advocates so that their views are not allowed to stifle the creative comments of the rest
of the participants.
During the Minus phase everyone points out
problems with the topic. Note that in the Plus phase even people who dislike the idea must
come up with things that are good about it and during the Minus phase even those who like
the idea must come up with problems with it. This has the effect of not allowing people to
argue only in favor of their position.
However, the real value is in the third phase, Interesting.
Here the idea is to essentially finish the sentence, "If we did this, it'd be
interesting to see if..." Note that the topics that come up here are ones that are
not inherently negative or positive. They often end up being unproven assumptions and/or
indications of how others will react. In many of the cases where I've used this method the
Plus and Minus phases, the ones traditionally thought to be the value of brainstorming,
are really just set ups for the Interesting phase, which actually produces the most
In the naysayer/devil's advocate discussion, I'd expect most naysayer comments to come out
during Minus phase along with other negative comments and the devil's advocate comments to
come out during the Interesting phase with other challenging but unproven comments and