Fishbone Diagram

The Fishbone Diagram, also called an Ishikawa diagram or cause and effect diagram, is a tool for identifying the root causes of a problem. A team draws a central line with the problem or effect at the end and adds branches for categories of causes, then lists potential causes within each category. The team analyzes relationships between causes, often using 5 Whys, and develops solutions for the identified root causes.

Source checked2/2 values · 2026-10-25Tool

Specification

1 source

Kind	tool
Origin	Developed by Kaoru Ishikawa in the 1960s

Study notes

Constructed with a horizontal line; the problem or effect is written at the end.
Lines coming off the central line represent categories of causes.
Typical categories include people, equipment, materials, environment, and methods.
Within each category, branches represent specific potential causes.
Teams brainstorm and list possible causes within each category before analyzing relationships.
The 5 Whys method involves asking why the problem occurs repeatedly until the root cause is identified.
After root causes are identified, solutions may involve changes to processes, equipment, training, or other contributing factors.
Include only actual physical causes; including wished-for or assumed causes can turn a fishbone into a "wishbone" diagram.
Used in manufacturing, healthcare, and service industries to identify and analyze contributing factors.