What it is 

A brainstorm is just a “gathering of ideas” from everyone who participates in the brainstorming session. Usually a theme, or a direction, is chosen and from that theme/direction everyone generates ideas. A simple exercise to perform but difficult to be effective at. 

How it can be used as a risk tool 

How do we use Brainstorming as a risk identification tool then? Simply by gathering up different people from a project, preferably the same project, and then putting them in the same room. A spokesperson or similar (project manager, risk manager etc.) will set the theme or direction of the exercise. Then it is simply a matter of hearing each other's ideas and then discussing them on based on the different perspectives each person has from their specific field of expertise.  

This exercise relies heavily on listening and not being a “no person”.