Ishikawa (Fishbone or Cause and Effect) Diagram

Definition: An Ishikawa diagram is the pictorial representation depicting the factors responsible for a certain problem in such a manner that the root cause is identified. It is a problem-solving approach which focuses on uncovering the effect of various factors over a particular issue.

This visual tool was brought to limelight by a Japanese engineer and quality control expert, Kaoru Ishikawa.

This layout appears like a fishbone where the head section depicts the effect or problem statement, and the middle body is seen as the multiple causes or factors. Thus, it is termed as a fishbone diagram.

The basic cause and effect diagram proposed in the 1960s comprises of the following ‘6M Categories’:

  1. Manpower: Human resource is a vital element of the organization and can be seen as a reason behind most of the corporate failures or achievements.
  2. Machines: A major part of the company’s finance is invested in the machinery and it is considered to be the backbone of corporate functioning.
  3. Methods: The business process including production or manufacturing are deemed to cause trouble such as non-compliance with the set standards and regulations.
  4. Measurement: This section list out the hurdles in analyzing efficiency, quality checks and other process measurements.
  5. Materials: The procurement, quality, purchase price, vendor selection, warehousing and handling of the raw material hold the core factors causing problems.
  6. Mother Nature (Environment): This part of the diagram enlightens upon the external causes of the trouble such as the political, social, economic, technological and demographic environment.

However, later on, this diagram was moulded as per the needs of the organization to include or exclude one or more categories. In the above diagram, we have shown two more categories i.e., management and maintenance.

Content: Ishikawa (Fishbone or Cause and Effect) Diagram

  • How to Create a Fishbone Diagram?
  • Example
  • Benefits
  • Disadvantages
  • Conclusion

How to Create a Fishbone Diagram?

While drawing the cause and effect diagram, many people get confused about where to start from?

Given below is a systematic and well-structured procedure of creating an Ishikawa diagram:

  1. The foremost step is to diagnose the exact issue being faced by the organization. It is stated under the ‘effect’ in the head portion of the fishbone.
  2. Next, state the categories under which the causes i.e., manpower, materials, methods, machines, measurement and environment are listed on the diagram.
  3. Now, find out the maximum possible causes or reasons contributing to the problem. Also, the team has to ascertain the link between different causes, to identify relevant branch bones.
  4. The major factors causing the issue are branched out as primary cause within their respective categories.
  5. The sub-causes i.e., secondary or deeper reasons are rooted under their concerned primary causes.
  6. The ultimate reasons or findings behind the secondary causes are attached respectively to complete the diagram.
  7. Lastly, a rigorous analysis of the whole diagram is done to inspect whether everything is in place. Also, a framework is prepared to determine all the possible means to resolve the issue.

Fishbone Diagram Template

A smartly drafted Ishikawa diagram can hit on the targeted issue to develop innovative solutions.

Let us take a glimpse of the overall structure of Ishikawa or cause and effect diagram below:

In the above picture, the categories can be replaced as per the industry’s need or business type.

For a manufacturing unit, 8Ms namely; manpower, materials, methods, machines, measurement, mother nature, maintenance and management are depicted.

While in service-based firms, 5Ss i.e., skills, systems, suppliers, surroundings and safety are used as categories.

Also, in the marketing industry, the category includes marketing mix’s 7Ps – product, price, place, promotion, packaging, positioning and people.

Fishbone Diagram Example

A fertilizer manufacturing company encountered an issue of decline in monthly production in one of its unit; even after the expenses and other inputs being constant. It conducted the Ishikawa diagram analysis:

The team came up with the following findings or root causes from the above diagram:

  • The unit comprises of many untrained workers which is the major factor behind under-productivity.
  • The leadership of the superiors is inefficient since they are unable to schedule proper training sessions for the newcomers.
  • These fresh hires are made to work directly on machines without providing sufficient orientation and training; which results in high production wastage.
  • Ultimately, the labour who are unable to handle the pressure leaves the job and the ones who stay back become lethargic.

The team now has the list of ground causes and can accordingly plan their actions to rectify the issue.

Benefits of Fishbone Diagram

The organization that adopts the Ishikawa diagram as a problem-solving tool can provide astonishing results or performance.

Let us find out the proven advantages of this technique:

Identifies Root Cause: To understand the root of the problem or say the ultimate cause of the issue, Ishikawa diagram is of great significance.

Establishes Cause and Effect Relationship: It is an appropriate way of stating the relation between what had happened and why did it happened.

Facilitates Curative Measures: As it uncovers the problem and its relative causes, finding the corrective measures or quick fix becomes effortless.

Visual Representation: Everything can be shown on a paper or screen, i.e., the problem, the causes and their correlation can be visually plotted and studied in an Ishikawa diagram.

Deeply Analyzes Problem Area: In the fishbone diagram, the problem and its roots are revealed thus simplifying the analysis and presentation process for the team.

Enhances Process: It improves performance as well as business processes. Since the loopholes in the production or functioning of the organization can be worked upon with the help of this tool.

Disadvantages of Fishbone Diagram

Creating a fishbone diagram is not a novice affair. It though looks simple, but when applied to a real-life situation, it gets tougher and confusing.

Thus, while preparing this diagram, its following limitations should not be neglected:

Lacks Evidence: The Ishikawa diagram is formed based on team assessment and opinion rather than the facts.

Multiple Root Causes: When there are various root causes, it becomes difficult for large organizations to take intense corrective actions.

Overemphasis Provides Irrelevant Outcomes: The excessive intensification of the various factors may extend the process unnecessarily, making it difficult for the team to compile everything for decision-making.

Requires Expertise and Skills: Of course, the fishbone diagram analysis reduces the managerial burden, however creating the whole picture is an adroit’s task.

Wastage of Time and Efforts on Insignificant Causes: Sometimes, in the urge of efficiency, the team invests time and energy in listing out the extraneous factors, which are later eliminated.

Democratic Selection of Causes: The team independently determine the factors or reasons behind a certain issue, which may at times be partial or incorrect.

Difficult to Depict Complex Correlations among Causes: When the cause and effect diagram includes numerous factors making it highly complicated for the team to inter-relate these causes.


An Ishikawa diagram is fruitful to solve some of the major concerns only when the team works together. Thus, everyone’s contribution or inputs help the company to investigate and bring out the hidden factors responsible for the problem.

The diagram should always be demonstrated over a large space (whether on paper or screen) leaving gaps in between the causes; so that additional factors can be incorporated at any point of time.

Also, the team members should always pose a question ‘why it happened’ while listing out each cause to reach out to the final root cause behind it.

Ishikawa (Fishbone or Cause and Effect) Diagram
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