PMI (plus, minus, interesting)

PMI—plus, minus, interesting—is a deliberate-attention tool for exploring an idea before deciding whether to accept or reject it. It is especially useful when a suggestion sounds impractical at first, because it separates exploration from advocacy and gives the group permission to notice possibilities that an immediate debate would suppress.

When to use it

• Use PMI to develop a new idea or examine one that is being dismissed too quickly.
• Use it when optimism, pessimism, hierarchy or group consensus is narrowing the discussion.
• Use it in brainstorming to protect contributors from ridicule and keep tentative ideas available for development.
• Do not use it as the final decision method when evidence, risk analysis or specialist judgment is required.

Origins

Edward de Bono developed PMI as part of his programme for teaching thinking as a practical skill. It belongs to his family of attention-directing tools: participants deliberately look in one direction at a time rather than defend an initial position. PMI can filter brainstorming output, but it can also generate ideas in its own right by revealing benefits, drawbacks and intriguing consequences that were not visible in the original proposal.

What it is

The three lenses are:

Plus

potential value, advantages, beneficiaries and enabling conditions.

Minus

costs, harms, constraints, failure modes and people who may be disadvantaged.

Interesting

questions, surprises, second-order effects, experiments and possibilities that are neither simply positive nor negative.

The categories are prompts, not a scoring system. Their purpose is to broaden attention before judgment. A balanced page does not mean the idea is sound, and one severe risk can outweigh many minor advantages.