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Benchmark Six Sigma - War Room

This post provides my responses to each of the five questions that were posed in “The Fishbone Game“. If you have not played the game yet, please proceed to play the game at https://benchmarksixsigma.com/blog/let-us-play-fishbone-game/, and revisit this post with your answers ready.

Question 1 – X is an identified cause for Y and Y is a negative undesirable effect. Is the following statement True or False? –

It is possible that X is neither necessary nor sufficient for Y to occur.

My response is – TRUE (matches approximately 57% of responses)

Let us consider an example of Sudden Cardiac Death (SCD)- Some of the great athletes maintaining very good general health have died due to SCD, which happens due to sudden cardiac arrest (SCA), a medical condition that can lead to death within an hour.

The most common reason cited for SCA is the coronary artery disease (CAD). However, presence of CAD is neither necessary nor sufficient for the occurrence of SCA. Continuing further with the why – why analysis, the reasons for CAD are quoted as the following (source – bostonscientific.com)

  • A family history of coronary heart disease
  • High blood pressure
  • High cholesterol
  • Obesity
  • Diabetes
  • Sedentary lifestyle
  • Smoking
  • Excessive alcohol intake
  • Age

Although, these are known causes, none of these individually or as a combination is a necessary condition for CAD. Also, none of these or any specific combination of these guarantees CAD. In this case, cause(s) is/are neither necessary nor sufficient for the occurrence of CAD.


Question 2 – X is an identified cause for Y and Y is a negative undesirable effect. Is the following statement True or False? –

In the quest to permanently eliminate Y, if X is found to be sufficient for occurrence of Y, we should consider just X as our focus area; X being necessary does not really matter.

My response is – FALSE (matches approximately 52% of responses)

Why-why analysis, Root cause analysis, Five Why Analysis, Fishbone Diagram, Fishbone Game, Cause and Effect Analysis, Cause and Effect Diagram

The image above gives one example where the cause of call drop is sufficient but not necessary. Moving to a no-coverage area is a sufficient cause for a call drop.If we want to eliminate call drops, ensuring that user will not move to no-coverage area is by no means a complete solution.


Question 3 – X is an identified cause for Y and Y is a negative undesirable effect. Is the following statement True or False? –

If X is found to be sufficient for occurrence of Y, it means that X must also be necessary for Y.

My response is – FALSE (matches approximately 53% of responses)

The figure and explanation provided for question #2 is sufficient but not necessary to provide a response for question #3. 🙂

Why-why analysis, Root cause analysis, Five Why Analysis, Fishbone Diagram, Fishbone Game, Cause and Effect Analysis, Cause and Effect Diagram

While ringing of a fire alarm is sufficient to create mass distraction at office work, it is not necessary for such widespread distraction. There are many more causes that can create mass distraction. Some examples are shown in the above image.


Question 4 – X is an identified cause for Y and Y is a negative undesirable effect. Is the following statement True or False? –

If X is necessary for Y, this means that the occurrence of Y is sufficient to prove that X has happened.

My response is – TRUE (matches approximately 63% of responses)

Why-why analysis, Root cause analysis, Five Why Analysis, Fishbone Diagram, Fishbone Game, Cause and Effect Analysis, Cause and Effect Diagram

Another example – Switching a source of music “ON” is necessary for a person to listen to it. If a person is listening to music, this is sufficient to prove that some source of music has been switched “ON” by someone, somewhere.


Question 5 – X is an identified cause for Y and Y is a negative undesirable effect. Is the following statement True or False? –

To permanently eliminate Y, the following must happen – We must be able to target and address a set of X’s, which is necessary as well as sufficient for Y to occur.

My response is – TRUE (matches approximately 87% of responses)

Why-why analysis, Root cause analysis, Five Why Analysis, Fishbone Diagram, Fishbone Game, Cause and Effect Analysis, Cause and Effect Diagram

In the above example, the following set of conditions are necessary and sufficient for inconsistency in gender and salutation.

  • The user selects one field correctly.
  • The user selects the other field incorrectly.

Jointly, these are necessary as well as sufficient for inconsistency to happen. In this example, there is an opportunity to eliminate inconsistency as the condition is actionable.


In this FISHBONE GAME so far, it is heartening to note that in all questions, the majority has matched my responses, although the margins are slender for questions 2 and 3. I invite you to comment and share your thoughts. Please use this link to comment.

Vishwadeep Khatri
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