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Ishikawa Diagram, Fishbone Diagram, Why-Why Analysis

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Fishbone Diagram


Fishbone Diagram (Ishikawa Diagram or Cause and Effect Diagram) - is a graphical tool to depict the potential causes for a specific problem/event/issue. Potential causes are identified as an outcome of the brainstorming activity.

The problem is shown as the head of the fish (on the right) and causes become the bones (on the left). Ribs branch off the main back bone as categories in which the potential causes are clubbed. The ribs can be sub-branched for root causes to as many levels as required.


An application oriented question on the topic along with responses can be seen below. The best answer was provided by Mohan PB on 17th November 2017. 




Q47.  What are some of the common ways by which Fishbone Diagram and Why- Why Analysis is misused? 


Note for website visitors - Two questions are asked every week on this platform. One on Tuesday and the other on Friday.

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The effectiveness of any tool is dependent on the user and method use. So is the case with the “Fishbone Diagram (FBD)” or “Cause and Effect Diagram (CED)”.


No tool can achieve anything not intended by the user of the tool. A tool can only provide different perspectives to the user to take a decision. It is very much possible for the user to junk the information the tool provides and go by his or her feeling. The “Fishbone Diagram” or “Cause and Effect Diagram” is no exception.


Misuse of a tool can also include erroneous use, which could be either a genuine error or an intended misuse.


Means to pre-conceived end

The most common misuse of the FBD is to doctor various bones so that all root causes that emerge are in line with decisions already taken. Logic can be thrown to the winds as each immediate and root cause are written so as to justify the decision.


Effects instead of causes

Another common mistake people can make is to reverse the plotting of causes as a hierarchy of effects. Rather than progress causes from the effect to the root cause, it progresses through subsequent effects.


Incorrect or inaccurate problem statement definition

A guess or an assumption is made when documenting the Problem Statement or Effect. Then with the effect itself not being very correct, of what quality can the supposed “Root Causes” be?


Too much of guess-work in the causes

While all proposed causes are to begin with atleast, potential causes, if too many causes are all out of guess work or out of assumptions without a validation plan, then the likelihood of the problem being solved is next to nothing.


Tracing back from the root cause

After reaching the root cause, by relentlessly questioning “Why?” a comfort syndrome results in picking up an immediate cause rather the root cause.


Using Solutions as Causes

To prepare a justification for investment in a solution, solutions end up getting prefixed by “Lack of”. Examples could be lack of automation, lack of maintenance support etc.


Giving up after identifying one Root cause

Either due to the excitement of having identified a root cause or due to sheer laziness, it is possible to forget the basic tenet that one problem may have multiple root causes.


Confusing correlation with causation

Mistaking certain commonalities in various instances of problem occurrence as the cause of the problem itself is another common error.


Working to a strict time deadline

While no activity can go on endlessly, it is not possible to brainstorm and think through all root causes in a hurry or when wanting to close the meeting within a particular time. Many staff who participate will take quite some time to warm up and by the time they are ready to contribute, the meeting is over.


Criticizing proposed root cause ideas

It takes free, unfettered thinking to arrive at all root causes. If the thought-process of the participants are stifled for any reason, the fish bone will not complete and thus not effective.


Holy cows

There are certain people or certain processes in the organization which are sacrosanct and cannot be touched, let alone be changed whatever be the consequences. Therefore, all root cause analyses stop at this point.


“Out of control” causes

To be on the safer side and not end up with responsibilities, it is best if the fishbone analysis is guided to causes not within the organisational control at all so that no one in the organisation is tasked with the responsibilities of implementing corrective action.


People related causes

Documenting clichéd people related causes like, “Human error” (Are animal errors possible?), “forgot” (Is the process so dependent on memory) will not help in resolving the problem.


Focusing on “Who” rather than “What”

A classical distraction is to focus on who is the root cause instead of what.

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The “FishBone” diagram, also referred to as “Ishikawa” diagram or “Cause & Effect” Diagram is a Quality tool to be used to stratify and narrow down the potential causes for a problem (effect), based on which focused attention can be given to continue the root cause analysis.


As a Quality professional, I do admit that on several occasions, this tool has not been applied the way it has been intended for. The following are some instances.


1.Drawing the Fishbone diagram, after the root-cause has been identified:

By passing the systematic team based approach expected by using tools such as Fishbone diagram, the cause identification is done and the Fishbone diagram is created afterwards to be used as a presentation in the Quality story.


2. Not used in the right sequence

Ideally a brainstorming has to be conducted first an all the ideas collected and compiled. Then they need to be stratified; best to use a tool like Affinity diagram before heading for fishbone diagram. There are suggested stratification headings given for problems related to Manufacturing, Service etc.; however, no hard & fast rule to stick to it, and one may customize the headings appropriately.

The sequence is sometimes not followed, and drawing the fishbone diagram is resorted to right away.


3. Primary branches not used for grouping

Each of the primary branch of the fishbone is expected to represent a stratified group of the causes. But sometimes instead of that, the primary branch is named using a cause itself.


4. Logical cause flow not maintained

The secondary branches need to be the causes within that primary branch’s group. Then we need a tertiary branch which represents the sub-causes for the primary causes. Sometimes the sub-causes are not judiciously organized to give a logical ‘why, why’ flow.


5. Mix up of stratification and causes

Sometimes the stratification points and causes are mixed up. Assuming we are working on a failure analysis for a product produced from 5 machines, if we split the failure data machine wise, it is not split up of the causes, but only stratification of the effect. Only if we try to answer a question viz. “Why did this failure happen?” we will go to the cause. For eg. “Run-out for Machine A is higher”.


6. “Effect” too broad

Sometimes we make the “Effect” very broad, for eg. “Quality Target Not Met”. This will end up deriving a fishbone, with even the tertiary branches referring ‘stratification’ and not ‘causes’.


7. Cramming of sub-causes

Sometimes we create too many sub-branches and the fishbone may become too crowded. If any particular primary cause starts branching out to many sub-causes, it may be prudent to create a separate Fishbone diagram for that primary cause


8. Mistaken Expectation

The fishbone as explained earlier is meant to identify all potential causes to maximize the collective exhaustiveness. Subsequent efforts are required to funnel and narrow down to the root cause(s). But sometimes the fishbone is interpreted as final cause list, and leads to confusions.

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Fishbone diagram is misused in the scenarios where process experts are not involved to bring out true causes of the effect. In case is all the required stakeholders from affected area are not involved then there is possibility of misrepresentation of facts in fishbone diagram. Selection of main bones of the fishbone analysis, key categories to analyze the problem if not done effectively then it leads to misuse. While the root cause is arrived at when a category of cause is analyzed if a detailed 5 why analysis is not done to arrive at core root cause then that leads to misuse as well. Another key thing to remember is correlation does not mean causation. So some in-depth thought process is not to arrive at appropriate causes of the problem.

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Ishikawa (Fishbone) Diagram is a  tool used to analyses Causes and their Effect.

The Effect is the problem to be solved indicated by the “head” of the fish. While the various possible Causes are brainstormed and listed (categories and sub-categories) on the body of the fish as branches i.e. the “bones”. Hence the name Fishbone diagram.

The causes are grouped in categories – Machine, Method, Material, Man, Measurement, Management, Maintenance, Mother Earth (Environment).

Subsequently, the various listed causes are given weights indicating their possible contribution to the problem and the team gets an idea of which causes to attack first.


It is a very helpful tool:

  • To analyze and find the root cause of complicated problems and the root cause is not clearly visible
  • To get an wholistic picture when there are multiple possible causes for a problem
  • If trial and error and exhaustive “brute force” methods to solve the problem could be expensive and very time consuming


Common Misuse of Fishbone Diagram:


  1. Using the Fishbone diagram for simple and known problems, which can be fixed without much difficulty
  2. Experts in the team may already know a solution to the problem and yet a Fishbone diagram is drawn.
  3. Using a single Fishbone diagram for multiple problems/ Effects. Each Problem/effect should have a single Fishbone diagram.
  4. Using it in places involving logic and reasoning where decision trees or flowcharts may be more apt.
  5. A Fishbone diagram developed for a problem may not be effective if the team size is too small for brainstorming or the team has limited knowledge regarding the process and issue. The causes identified may be limited and may not cover all possible causes.
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Fishbone diagram also known as ishikawa diagram created by a Japanese quality poineer named ishikawa.  It is closest translation in factor and effect analysis.  In other words we can say that is is cause and effect analysis.  In which effect is at extreme right side and cause are in left side divided like bones of fish and then sub divided into many more factors which relates to effect or problem. Effect is the problem that we want to solve. Where we don't know causes we need three things one is specific topic,  another is verification or prioritisation an d third one is brainstorming which is quality vs quantity. 

Fishbone diagram is used to identify root cause of a problem.  We can use it for chronic problems only.  For sporadic problem we should use why why analysis to find out root cause.  In manufacturing industry we use normally 5 M and one E,  for service industry 4 pm.  There are different factor so which are categorised then we do find out potential cause by brainstorming and interrelate all with defined category and so we find out a relation between all and reach a root cause which is affecting the problem. It may be possible that one potential cause relates to two category like lack of training relates to manpower and in machine knowledge also.  So we need to do carefully all analysis and find out root cause by discussing. 

There are several ways by which fishbone diagram is misused.  We do fishbone analysis of any problem or any sporadic problem which is not relevant because for that we can do why why analysis.  We start to fishbone by focusing on quality idea but we should focus on quality of potential causes.  For this team size should be from 5 to 7 people to diversify and it should be cross functional team so that we can have potential cause from all.  Another way to missuse of this that we start without involving all team members and start to write without discuss with all.  No one agrees on anything in the team.we start to finish d out relationship between causes without listing down all.  We should first list down all,  then do categorise and find root cause.  People start to ride on others idea that is wrong.  People tries to evaluate or censor ideas before end of session. Normally we should avoid all these because by doing all we can use fishbone properly and misuse of fishbone will not give fruitful result.  

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A fish bone diagram displays graphically the factors and underlying causes of a defect or problem. The factors are drawn on lines radiating out from a central line. The completed diagram resembles a fish skeleton hence it is called Fish bone diagram.

Other names:-

1.     Cause and effect diagram ( as it shows relation between all the causes and it’s effect)

2.     Ishikawa Diagram (named after it’s creator Kaoru Ishikawa)

The fishbone diagram gives you a comprehensive list of possible causes to identify the root cause of the problem.

We can group causes in separate categories as per industry it is used.

For manufacturing industry, we can use 6M’s (Man, Machine, Method, Material, Management, and Mother Nature)

For marketing industry, we can use 7P’s (Product, Price, Place, Promotion, People, Positioning, Packaging)

For service industry, we can use 5S’s (Surrounding, Suppliers, System, Skills, Safety)

It is not mandatory that we need to stick with these categories for any industry; we can add/modify categories as per our requirement.

Advantage of grouping causes as per category is to get as many possible causes for the problem.

Sometimes people are having presumptions about the causes, and they do not think outside those causes. Having different categories help people to think in all the directions.

Below is an example of Fishbone diagram in a Manufacturing industry.






Fishbone Diagram is considered misused for following reasons.



1.     Problem statement not clearly defined. Clarity of problem for all the team members is essential for brainstorming of causes for a fish bone diagram.

2.     Team selected for brainstorming should have people who are subject matter experts, otherwise there will be few causes on the diagram and we may not reach the root cause.

3.     People in team are not open for other causes, and support the causes that they presume is root cause.

4.     If we don’t keep all the points, thinking that it is having negligible impact.

5.     We get symptoms on the list instead of causes.

6.     Why Why analysis for a cause is not used effectively.

7.     Stopping the session, because there are too many causes on the bone and no more blank space available.

8.     Stopping the session because of time constraints

9.     Discussing more about a particular cause and hence diverting the topic to some other problem.

10.  Further filtering of all the causes is required with help of other tools.





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Ishikawa Diagram or Fishbone diagram is also called Cause and Effect Diagram, it is used to identify, explore and graphically display, in increasing details, important possible causes related to a problem or condition to discover its root cause.

The fishbone diagram gives a comprehensive list of possible causes to identify the root cause of the problem. The fishbone diagram uses a brainstorming technique to collect the causes and come up with a kind of mind map which shows you all identified causes graphically.

Fishbone diagram can be used in any industry and it can be customized based on the cause and its effect. However some popular customized Ishikawa diagrams used in deferent Industries are below……

  1. Manufacturing Industries uses 6 Ms. factor (cause) .





                 Measurement (Inspection)

                 Milieu (Mother Nature – Environment)



The first six were populated by Toyota, and later on two more “Ms” were added to the list.

  1. Marketing industries uses 7Ps factor (cause)








  2. Service industries uses 5Ss factor (Cause)






How to do it:

  1. Select the most appropriate Cause & effect format

  2. Generate the cause needed to build a cause & effect diagram, using either

    1. Brainstorming without previous preparation

    2. Check sheets based on data collected by team members before the meeting

  3. Construct the cause & effect diagram

    1. Place the problems statement in a box on the right-hand side of the writing surface

    2. Draw major cause categories or steps in the production or service process. Connect them to the backbone of the fishbone chart. If any bone is becoming too bulky, try to split it into two or three branches.

    3. Place the brainstormed or data-based cause in the appropriate category.

    4. Ask repeatedly of each cause listed on the bones.(For deeper cause ,continue to push for deeper understanding, but know when to stop. A rule of thumb is to stop questioning when cause is controlled by more than one level of management removed from the group. Otherwise, the process could become an exercise of frustration.)

    5. Interpret or test for root cause by one or more of the following

      1. Look for cause that appear repeatedly within or across major cause categories

      2. Select through either an unstructured consensus process or one that is structured ,such as Nominal Group Technique or Multi-voting

      3. Gather data through check sheets or other formats to determine the relative frequencies of the different cause.

While it helps in finding bottlenecks in the process, identify ways to improve the process and the root cause of the problem but sometimes it gets misused.

Fishbone diagrams are misused in the following ways.

  • If the participant is less experienced, less involved and not more knowledgeable, the diagram will be very neat and clean and might not be able to identify the root cause of the problem.

  • When the discussion/brainstorming session is not controlled properly it may deviate from its objective.

  • Voting down the causes, may not be an effective way of identifying causes but the diagram follows opinion based methodology rather than evidence, this process involves a democratic way of selecting the cause.

  • Sometimes it happens that the most obvious cause turns out to be minor and the cause thought to be a minor one was causing the issue. As the fishbone diagram Follow the divergent approach, it forces the team to consider all possible causes of a problem instead of focusing on the most obvious one.


Ishikawa Diagram or Fishbone diagram.docx

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When utilizing a team approach to problem solving, there are often many opinions as to the problem's root cause. One way to capture these different ideas and stimulate the team's brainstorming on root causes is the cause and effect diagram, commonly called a fishbone. A fishbone diagram, also called Ishikawa diagram, is a visualization tool for categorizing the potential causes of a problem in order to identify its root causes. Drawing a fishbone diagram requires asking “Why?” as many times as necessary to try and reach the roots of a problem and is used to analyze problems systematically. When used in theory this makes so much sense but in reality most of the problem causes are already solved so using the 5 whys techniques never quite hits the mark. It helps only in understanding problems and not in goals and reasoning. “Why” in psychotherapy is seen as a dangerous question.  From a purely human perspective it can be confrontational and seen as judgmental. One should ask very specific questions based on context and encourage introspection in a safe or well-judged manner else it may backfire. After the group has brainstormed all the possible causes for a problem, the facilitator helps the group to rate the potential causes according to their level of importance and diagram a hierarchy but this may also be misinterpreted.
Here is where these two conditions come into play.
Necessary Condition – A condition is necessary if absence of the condition guarantees absence of the effect.
Sufficient Condition – A condition is sufficient if presence of the condition guarantees the presence of the effect.
The real question now is whether being necessary and/or sufficient really important and to find its exact role in problem solving.
Thus the effective use of Fishbone or the Why-Why analysis depends on the kind of causes we identify or get satisfied with. This tool requires many other techniques like DMAIC in addition to solve complex problems. Just as starting right is important, it is also important to know when to end the cause analyses. Most of it depends on asking the right questions. Necessary and Sufficient conditions form an integral part of this analysis.
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Fishbone Diagram is used to find the possible causes for a problem- Eventually it helps to narrow down to the Root cause for the problem under study, if the analysis is done effectively. This method comes handy especially when the team’s thinking before the session is not aligned and there is a need to get all on the same page- literally!!

The facilitator of the session holds the key to the success of the session, As there are chances for the whole exercise going off track and leading to NVA. The Facilitator plays the champion of the purpose of the session and takes it forward like a project with a proper BOSCARD handy and briefs the team before the session starts- He ensures that theer are enough people who are stakeholders of the concerned process and will provide inputs that will provide valuable insights towards the purpose.

It helps if there is a judicious distribution of the “Six thinking hats” within the team to provide a logical and valid output at the end of the session.

Having said that the Fishbone diagram can be misused as well-

There is every chance that the process to draw the fishbone diagram is taken far too “word to word” and the “whys” can be misused or wrongly used. There is every chance that the why can be put forth as an unwelcome question, purely from a human perspective- It can be taken as a confrontation and the answers that come forth can be defensive towards the functions in which a participant is a team member.

The purpose of the session is Unclear- The purpose of the whole exercise is not specified before the session and there is no alignment on the “end” of the session- This can lead to out of context approaches and create an ineffective fishbone diagram.

Sometimes the causes (inputs) are prompted by the participants who are superior in position and their calls influence the others- This can lead to a complete dilution of the purpose as it discourages consideration and introspection.

The biggest misuse of the Fishbone diagram is when it is used in situations where it is not to be used at all-

-          The Problem is simple and is already known and has been worked upon earlier or for that matter there are already some members who are expert in the the subject matter and can resolve the problem - Utter waste of time.

-          The team size is too small for brainstorming – The output is limited and the whole activity is not relevant then.

-          There is time constraint – Immediate closure is required and all or sufficient headcount is not sufficient for the brainstorming

-          There is a communication gap within the participants- Biggest roadblock to an effective outcome

What happens in these situations is that the whole exercise is done just for the sake of doing it- Absolute misuse of the fishbone diagram because the outcome of such sessions – the fishbone diagram , will either not be relevant or will not produce expected results.

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Ans: Cause and effect diagram is called a fishbone diagram and also known as Ishikawa diagram, which will help to identify the possible causes of a problem and in sorting ideas into categories. A fishbone diagram is a visual way to look at cause and effect. It is a more structured approach than some other tools available for brainstorming causes of a problem (e.g. the Five Whys tool).

Whoever using the fishbone diagram has to follow the below steps,


· It should have started with a defined problem statement (also referred to as the effect), which should be written in head of the fish. Should be clear and specific about the problem.

· Need to identify the major categories of causes of the problem, should be written as branches from the main arrow. Eg: Equipment, environment, Manpower, Material etc

· Brainstorm all the possible causes of the problem with team. Ask members to write it in a white paper to share as much as causes and ideas for the problem statement.

· Need to categorize the possible causes into major categories to arrive at the vital causes of the problem

· This will help to identify and address root causes to prevent the future problems.


Common ways by which Fishbone Diagram is misused are,


· Asking more “whys” to identify the possible causes from team will leads to, getting incorrect causes of problem due to frustration or by panic of receiving more “whys” from the supervisor or facilitator.

· Brainstorming will give the relevant and irrelevant potential causes of the problem, which will drain the energy

· Often the efforts are wasted in identifying causes as a fishbone diagram is based on opinion of the team rather than evidences. This concept involves independent way of choosing the cause, which may not be an effective way of identifying the causes

· Same possible causes can map in multiple major categories like material, man etc and which will change the focus of an improvement area

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Q48.  What are some of the common ways by which Fishbone Diagram is misused? 


Fishbone diagram is also called as ishikawa diagram or Cause & Effect diagram. It is a visual tool used to segment the possible causes that is impacting the final product or service. It is helpful for identifying the root cause that is creating the problem.

Brainstormed ideas are collected and structured in the way using fishbone diagram. This helps categorizing the ideas gathered immediately into fishbone to identify the root cause.


Types of Fishbone –

Ø  Process fishbone

Ø  Time –delay fishbone

Ø  Cause & Effect diagram with additional cards

Ø  Desired result fishbone

Ø  Reverse fishbone diagram



Professor Ishikawa created this cause and effect diagram in 1960’s.. This diagram based approach is used to think through all the possible causes that is creating the problem. This helps to carry a thorough detailed analysis of the problem.


Steps to be followed:

There are four ways how you have to use this diagram. They are as follows.

1.       Identify the problem

2.       Brainstorm the factors or all X’s involved.

3.       Categorize and identify possible causes

4.       Analyze the diagram




Tools used

Identify the problem

identify the problem and write it at the head.
Also gather data relating to who has done it, why it is done, where it is happening, what is the impact, what process is involved

3W1H technique is used to narrate the problem statement effectively.

Work out factors involved

Brainstorm and list all the factors or X's involved, irrespective of its criticality.
If required, mark all these in white board for all members understanding and coordination.

Brainstorming is used to list the factors

Identify the possible causes

Brainstorm each of the factors listed above separately and draw as each of the bones of the fish. If required, the causes can be broken further into sub causes.

Brainstorming is used to list the possible causes

Analyze the diagram

After completing the entire diagram, depending on the criticality and complexity of the cause and problem, investigate further using why why analysis and so on.

5Why analysis,  Prioritization matrix, Multivoting technique to priotize the possible causes.



Fishbone framework:


1.       5M – Methods, Materials, Manpower, Measurement, Machines and environment

2.       5P – policies, procedures, people and plant, and place. (By service industry)

3.       7S – Strategy, Structure, systems, shared values, Skills, Style, Staff (used by McKinsey)

4.       4P – Product, place, price, promotion (used by Marketing)


Example –

A person having frequent sore throat think through and list all the possible causes in the fishbone diagram. Here it looks like. The possible cause of this issue is lifestyle. There can be many root causes to it. Modifying the lifestyle will help improve the condition of the person. Hence this is how it should have been done.



Possible ways of Misusing the fish bone:


1.       Limited thinking will not solve the purpose of using fishbone. Eg. If there is a time constraint during brainstorming session, the more information will not be collected due to other work related pressures.

2.       Limited resources: If the person gathering is freeze with only 6 or 7 categories, then he may be in a position to categorize all the factors into these factors listed only. Resource can be in the form like paper and pen, time, whiteboard, employees involved in the process. Verbally conducted RCA session using fishbone will result in listing relevant and irrelevant possible causes into the diagram.

3.       Inefficient people: If the fishbone is done using inefficient people, then there exists a failure. Fresher may not know the end to end process. In such case, if the fishbone is done using these fresher’s, the possible causes may not be a true event. It is vice versa. Hence a mix of tenurity should be involved in brainstorming and fishbone diagram.

4.       Biased in collection of information: During brainstorming, all the team members should be involved and all the ideas should be noted down. If there is any subjective bias in noting down the points or self-judging the causes will not lead into an effective RCA using fishbone diagram.

5.       Biasness in effective decision making: when the possible cause is irrespective of its relationship to the problem, the decision making becomes a waste. It may not yield you a best result. Inappropriate categorization of possible factors, and having the same point under multiple categorizes might lead into wrong decision making on the possible causes that affects the problem.




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Fishbone Diagram:-

Fishbone diagram is used as a tool for finding the root causes of an issue or effect. In this diagram 5 Ms are used as segmentation to identify the root causes under each segment.


How can this diagram could be misused ?!

It is quite possible that this diagram could be misused in many ways. Few of the possibilities according to me are below. .


1. Suppose while identifying the root causes under each segment, it is quite possible that we usually start from 1 M & just keep going to record all the issues under just one M ( First M). Meaning by the time we move to any 2nd M, we will end up in the situation where we have no further root causes left to record under 2nd M or remaining Ms. 


2. Now in order to ensure that we cover all the Ms, we may decide to record say 5 each per M. This is one way of misusing the diagram where we end up recording a minimum count of root causes. In such cases, we may miss out the actual root cause.


3. It is quite possible to misuse the diagram by repeating the the same root causes under each of the 5 Ms, or more than 2 Ms. In such case we may miss out the actual focus required on the cause with respect to the segment.


4. We could also misuse this diagram by using it where it is not feasible to use. Say for example, in certain businesses, the 5Ms are not existing fully or 1 or 2 or 3 Ms are not actually exists. In some service industries, the so called  Machines are not at all used, hence using Machine as one of the Ms may lead to in appropriateness of the analysis.


The above are few I feel could be some possibilities where the diagram could be miss used.


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What i have practically experienced, Fishbone Diagram (which is a powerful root cause analysis tool) can be miused in following two ways:

1) When we already know the root cause of the problem and still develop a beautiful and impressive Fishbone Diagram just for fun sake!

2) When we don't involve all the stakeholders and try to develop a Fishbone Diagram single handedly.

I feel use of Fishbone Diagram in root cause analysis is a collective exercise and hence shall be done in a systematic and honest manner.

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Fishbone Diagram

It is also called cause and effect diagram or Ishikawa diagram. It is a visualization tool for categorizing the potential causes of a problem so as to identify its root causes. This technique was created by Kaoru Ishikawa.   Each cause /reason for imperfection is a source of variation.


How the tool is misused?

1.       Often people (junior members or less experienced team members) misunderstand that this technique would set actions to solve the problems.  But this is not the case. Only root causes alone are specified

2.       This tool is not about single cause, but about set of causes that can be affect the outcome. But unfortunately people working on this does not focus on the whole lot

3.       For most of the type of problems across industries, this tool /technique can be useful. But with this tool alone, people try to provide the response which may be not correct. For instance, differentiating common causes and special causes, this tool can give some pointers. But to find how much impact the special causes create on the process or in your problem cannot be determined by this tool. You need a tool like Paretto chart. This sometimes team do not understand


 Eg: For Late Delivery of a pizza  - there could be any number of causes




Late Delivery of Pizza

Edited by R Rajesh
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Dear all, this is classic example of good learning initiative for all of us. We all know Ishikawa diagram is one of the easiest tool to use for RCA.


However alone we may not think through in this detail to understand pitfalls and misuse of such a simple but effective tool.


Most of the answers addressed what and how of Fishbone diagram and also addressed the pitfalls that might render the use of this tool ineffective.


The best three answers were from Mr. Venugopal R., Mr. Mohan P.B. and Mr. Ronak.  The most suitable answer addressing the misuse of the tool was from Mr. Mohan P.B..


Congratulations to you Mr. Mohan.

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