Value of brainstorming

Absolutely, if conducted properly. Brainstorming works primarily because the rules suspend judgment and the process stimulates thought.

The brainstorming rule "reserve all judgment - good or bad," removes barriers to presenting ideas. Participants in the brainstorming process are able to make new connections, dig deeper and focus on ideas in the brainstorming setting. Further, they feel safe enough to present "off-the-wall" ideas that are either good on their own merit or might stimulate another better thought.

Even good judgment, "I like that idea," for example, can slow or stops the creative process. Criticism, "That's stupid. We tried that before," is guaranteed to stop the process. It's human nature.