An Ishikawa diagram, also known as a fishbone diagram or cause-and-effect diagram, is a tool for identifying potential factors that cause an overall effect. It visually displays the potential causes for a specific problem or event, with major categories and sub-branches extending from the problem like fish bones. Kaoru Ishikawa popularized the fishbone diagram in the 1960s to help identify root causes of quality issues in manufacturing. The diagram considers all possible causes rather than just the obvious ones and groups causes to identify sources of variation.

1. Ishikawa fishbone
diagram

2. Ishikawa diagram are causal diagrams created by Kaoru
Ishikawa that show the potential causes of a specific event.
Common uses of the Ishikawa diagram are product design and
quality defect prevention to identify potential factors causing
an overall effect. Each cause or reason for imperfection is a
source of variation. Causes are usually grouped into major
categories to identify and classify these sources of variation.
Introduction

3. This diagram looks like a fish skeleton; the head is the
problem and the causes are connected with the spine;
therefore, many experts call it a fishbone or herringbone
diagram, or Fishikawa, for the same reason.
Since this tool helps you find the cause of the problem,
it got the name cause and effect diagram.

4. What is fishbone diagram
If you have any problem with your process or product,
you should know the cause before thinking about any
solution.
A fishbone diagram helps you to find the cause of the
problem. It gives you a comprehensive list of causes to
find the root of the problem.
This tool provides you with a better understanding of
the problem and makes sure you don’t just partially
solve a problem.

5. The fishbone diagram uses a brainstorming technique to
collect the causes and show them graphically.
Sometimes, the most apparent cause turns out to be
minor, and the one that was thought to be minor is
causing the issue. This diagram gives you an
opportunity to think thoroughly about the root cause,
which leads to a healthy and long-lasting resolution.
The fishbone diagram considers all possible causes of a
problem, instead of focusing on the obvious one, and
groups causes to identify the source of the variation.

6. The defect is shown as the fish's head, facing to the right,
with the causes extending to the left as fishbone; the ribs
branch off the backbone for major causes, with sub-
branches for root-causes, to as many levels as required.
Ishikawa diagrams were popularized in the 1960s by
Kaoru Ishikawa, who pioneered quality management
processes in the Kawasaki shipyards, and in the process
became one of the founding fathers of modern
management.
Overview

7. The basic concept was first used in the 1920s, and is
considered one of the seven basic tools of quality
control. It is known as a fishbone diagram because of its
shape, similar to the side view of a fish skeleton.
Mazda Motors famously used an Ishikawa diagram in
the development of the Miata (MX5) sports car.

8. Advantages
•Highly visual brainstorming tool which can spark further examples
of root causes
•Quickly identify if the root cause is found multiple times in the same
or different causal tree
•Allows one to see all causes simultaneously
•Good visualization for presenting issues to stakeholders
Disadvantages
•Complex defects might yield a lot of causes which might become
visually cluttering
•Interrelationships between causes are not easily identifiable.

9. These following are the steps to draw a cause
and effect diagram:
1.Identify the Problem
2.Identify and Categorize Causes
3.Brainstorm Possible Causes
4.Analyze the Diagram
How to Draw fishbone

11. •Man / mind power (physical or knowledge work, includes:
kaizens, suggestions)
•Machine (equipment, technology)
•Material (includes raw material, consumables, and
information)
•Method (process)
•Measurement / medium (inspection, environment)
Originating with lean manufacturing and the Toyota Production
System, the 5 Ms is one of the most common frameworks for
root-cause analysis
The 5Ms

12. •Product (or service)
•Price
•Place
•Promotion
•People (personnel)
•Process
•Physical evidence
•Performance
This common model for identifying crucial attributes for
planning in product marketing is often also used in root-cause
analysis as categories for the Ishikawa diagram
The 8Ps

13. An alternative used for service industries, uses four
categories of possible cause
•Surroundings
•Suppliers
•Systems
•Skill
The 4Ss

14. A fishbone diagram is a vital tool in identifying the root
cause of a problem. Although using it is time-
consuming, the benefits are enormous. This tool helps
you remove the root cause of the problem and develop
an understanding among team members. You use the
fishbone diagram with a critical problem because you
cannot spend much time on every small issue.
Summary