一般的に「ブレイン・ストーミング」というと、近未来EC研究会 第3回(mixi上のコマースに関するブレイン・ストーミング)で実施したような方式よりも、制約の少ないルールで行うことでしょう。例としてデザイン・ファームIDEOの設定しているルールを紹介します。

Seven Brainstorming Rules

Defer judgment
There are no bad ideas at this point. There will be plenty of time to judge ideas later.
encourage wild ideas
It's the wild ideas that often create real innovation. It is always easy to bring ideas down to earth later!
Build on the ideas of others
Think in terms of 'and' instead of 'but.' If you dislike someone's idea, challenge yourself to build on it and make it better.
stay focused on topic
You will get better output if everyone is disciplined.
Be visual
Try to engage the logical and the creative sides of the brain.
one conversation at a time
Allow ideas to be heard and built upon.
go for quantity
Set a big goal for number of ideas and surpass it! Remember there is no need to make a lengthy case for your idea since no one is judging. Ideas should flow quickly.

Brainstorming warm-up

Use this activity to get the team in an open-minded try and energetic mindset for brainstorming.

Pair up with a partner. Person A will come up with lots of ideas about a potential business he or she wants to start. (Alternatively, one could plan an event such as a family vacation and pose ideas of places to go.)

Rround 1:
Person A comes up with one idea after another. Person B must say NO to each idea and give a reason why it wouldn't work. Do this for 2-3 minutes.
Rround 2:
Now Person B comes up with business or event ideas, one after another. Person A must say YES to each idea and build on it to make it bigger. Do this for 2-3 minutes.

As a group, discuss how these two different experiences felt. The Round 2 experience is the environment the team will want to create for a successful brainstorm.

出展:Human Centered Design Toolkit: 2nd Edition, pp.73-74