Final answer:
Project managers can use a fishbone diagram to brainstorm potential causes of risks, identifying and categorizing all possible causes in a structured visual format.
Step-by-step explanation:
Project managers can brainstorm the potential causes of risks using the fishbone diagram, which is also known as the Ishikawa or cause-and-effect diagram. It is a visual tool used to systematically identify and present all possible causes of a problem, categorized into major factors affecting the issue. The diagram resembles the skeleton of a fish, with the 'head' representing the problem to be solved and the 'bones' indicating potential causes branching out into fine details. This method encourages thorough analysis and helps teams to think beyond the obvious reasons for a risk or problem.