PMI (plus, minus, interesting) is a brainstorming activity that encourages participants in a discussion to look at an idea from more than one viewpoint.
PMI was developed by Dr. Edward de Bono, a proponent of teaching critical thinking in schools. Dr. de Bono is credited with inventing the term lateral thinking, an approach to problem solving that encourages thinking about the problem in a creative, non-traditional manner. The goals of PMI are to help participants see both sides of an argument and think more broadly about an issue. Dr. de Bono felt that one of the problems with traditional thinking is that people focus their attention on how to back up an opinion that has already been formed. PMI is designed to open up each participant’s thinking and encourage creativity.
In an agile or scrum retrospective, PMI can be a useful tool for beginning the retrospective or unsticking the group when discussion has gotten bogged down. (Example: "Let's do a quick PMI on this.") The activity is short – it was designed to last only three minutes. Participants simply answer three questions as they apply to a topic provided by the facilitator -- listing what is positive, what is negative and what is interesting.
For example, when used as a warm-up activity for an iteration retrospective, PMI might look like this:
• What are the positive things about this iteration? (1 min.)
• What are the negative (minus) things about this iteration? (1 min.)
• What was interesting about this iteration? (1 min.)
See also: six thinking hats
Continue reading about PMI:
Naomi Karten describes one of her favorite team exercises, PMI.
Bill Wake includes PMI as one of the tools he recommends for iteration retrospectives in Patterns for Retrospectives.