What is Plus, Minus, Interesting (PMI)?
PMI is a brainstorming technique for gathering feedback on an idea, concept, or when a team takes a retrospective look at a recently completed set of work. After introducing the idea, the group is asked to write individual notes about what they found positive (plus), negative (minus), and what they thought was neither good nor bad but interesting. Feedback is shared and charted in the three categories, then discussed by the group.
There are several related techniques that use different categories for stimulating critical thinking, such as De Bono's 6 Hats Technique; Plus-Delta; Start, Stop, Continue; and 4Ls (Liked, Learned, Lacked, Longed For).