Ishikawa Cause-Effect Keynote charts - structured method used to determine the possible causes of an unwanted event or problem. He systematizes possible influencing factors into generalized categories in such a way that allows us to consider all possible hypotheses. However, the method does not indicate actual causes, since they can only be determined through actual evidence and empirical testing of hypotheses. Information is presented in the form of Ishikawa Cause-Effect Keynote charts (also called fish bones), sometimes in the form of a tree diagram.