Brainstorming is an activity used to generate ideas in small groups. The purpose is to generate as many ideas as possible within a specified time-period. These ideas are not evaluated until the end and a wide range of ideas is often produced. Each idea produced does not need to be usable. Instead, initial ideas can be be viewed as a starting point for more workable ideas. The principle of brainstorming is that you need lots of ideas to get good ideas.