Alex Osborn, an advertising executive, published Applied Imagination in 1953 and gave the world a word for what creative teams had been doing informally for years. Brainstorming is a group technique for generating ideas. The rules are simple: defer judgment, encourage wild ideas, build on others, and go for quantity. The point is to separate idea generation from evaluation. Critiquing too early kills the flow.

Classic brainstorming has its critics. Studies show that groups often produce fewer and less original ideas than individuals working alone, partly because of social loafing and fear of judgment. Many teams have adapted the method. Brainwriting has participants write ideas before sharing them. Nominal group technique has people generate ideas individually, then discuss as a group. Design sprints at Google Ventures combine silent ideation with structured critique. The common thread is that structure helps, and unstructured free-for-alls often do not.

Making it work

• State the problem clearly before starting.
• Separate generation from evaluation.
• Encourage wild ideas and build on them.
• Use silent writing before group discussion.

Brainstorming is not magic. It is a tool. Used well, it opens possibilities. Used badly, it wastes an afternoon and produces the same ideas the team already had.