Fishbone Diagram — What is it? — Lean Enterprise Institute Apr 10, 2023 · A fishbone diagram, also known as an Ishikawa diagram or cause and effect diagram, is a tool used to identify the root causes of a problem. It is named after Japanese quality control expert Kaoru Ishikawa, who developed the concept in the 1960s. Organizations across a variety of industries, including manufacturing, healthcare, and service use ...