Cause and effect diagrams, also known as Ishikawa diagrams, are one of 7 basic tools of quality. Cause and effect diagrams are useful because they let you list out all the causes that you and/or your team can think of. Having a team think of possible causes is similar to the concept of peer review in software development projects. Where one person thinks of a few causes, another person will think of different causes. This gives a broader range of causes to investigate.