Ishikawa Analysis

About Ishikawa (Fishbone) Diagram

The Ishikawa diagram is used to capture all potential factors that may contribute to a problem.

Capture potential causes of the problem to be resolved

The output of the Ishikawa diagram is a prioritized list of potential factors to be analyzed.

Ishikawa Kaoru (1915-1989) developed this diagram while working for Nissan Liquid Fuel. He is known as one of the fathers of quality management in Japan.

The Ishikawa-Diagram was later integrated into the seven quality tools of the Japanese Union of Scientists and Engineers (JUSE) where Ishikawa Kaoru was a member since 1949.

The Ishikawa-Diagram is also known as Fishbone Diagram or Cause-Effect-Diagram.

Worksheets

Ishikawa (Mind Map)

Qualica does not implement the fishbone diagram for ishikawa. Instead a Mind Map is used to edit the problem statement, influences, hypotheses, and analyses.

1
Start your Ishikawa Analysis by entering the problem statement into the dark grey root box of the mind map.
2
In case the problem can be divided into several sections, you may use the main menu, the right-click-menu or Ctrl+Return to insert sub items.
3
You can add the "6M" groups to any item in the mindmap:
- Activate the Home menu
- Choose Insert Group Headers - 6M from the extended insert menu
4
Add possible influences as sub items of the 6 groups using the insert menu or Ctrl+Return
5
By using Insert Hypotheses from the Insert menu you may add hypotheses to your influencing factors.
6
New Analyses from the Insert menu will add an analysis to a hypothesis.

Hypotheses

This worksheet documents the hypotheses you have put forward in the ishikawa analysis.

1
Hypotheses
This is the list of all hypotheses from the ishikawa mind map.
2
Hypotheses Table
For each hypothesis (row) not down:
- the alternative hypothesis
- the test to be performed to approve or disapprove the hypothesis
- the data to be used for the test
- the result of the test
- the conclusion you draw from the result
3
Analyses
The Analyses column shows all analyses connected to a hypothesis.

Analyses

1
Analyses
This is the list of all analyses mentioned in the ishikawa diagram.
2
Table
Enter more information about the analyses here.

Cause-Effect Matrix

1
Causes
This is the list of causes. Here: a generic list of parameters. It can also be linked to the list of design parameters or the process parameters.
2
Importance
Importance table of causes. Values are calculated by linear mapping from the effect importances and the central matrix.
3
Effects
This is the list of effects. In this example effects are the CTQs (critical to quality) from QFD but it can be any other list of items. Those items should be measurable and should have a unit.
4
Importance
Importance table of the effects. Values here may come from common prioritization methods, e.g. AHP or from a QFD matrix.
5
Specifications
This is the table of specifications for effect items - primarily the unit of the elements.
6
Details
This table contains more information about the causes.
7
Levels
This list contains the different settings for DOE planning and evaluation.
8
Cause-Effect Matrix
This is the central matrix of the worksheet. Set a relation wherever a cause (row) has an influence to an effect (column).
9
Selector
The central matrix can store different analyses with different relation values. For example you can start by documenting initial knowledge, and later the results of an experiment. This selector allows you to switch between the different sets of data.

Templates