A frequency histogram of attribute data arranged by category. You use this chart to identify the defects that most frequently occur.

A graphical tool for ranking causes from most significant to least significant. It is based on the Pareto principle, named after 19th century economist Vilfredo Pareto, and suggests that most effects come from relatively few causes; that is, 80% of the effects come from 20% of the possible causes. Also known as the "80-20 rule". One of the “seven tools of quality”.