For what kind of situation is a fishbone chart useful?

A fishbone chart is helpful for mapping out possible causes for a problem or identifying the potential effects of a given situation. Also called a cause-and-effect diagram, a fishbone chart is good for use in a brainstorming session.

To draw a fishbone chart in an effort to determine possible causes, one draws a box at the right side of a board or paper with the effect or problem listed inside it. A horizontal arrow runs to the box from the left side. Branches from the arrow contain major categories of possible causes. Further branches list causes relevant to a particular category. Asking "why" for each entry encourages deeper thinking about the problem until no more ideas arise.