1. What are the five whys?
A To o l F o r R o o t C a u s e A n a l y s i s
T i p s f o r a s i m p l e r w a y o f w o r k
S u m i t K u m e r B a n e r j e e
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P r e s e n t e d b y
2. What are the Five Whys?
Five whys (5 whys) is a problem-solving method that explores
the underlying cause-and-effect of particular problems.
The primary goal is to determine the root cause of a defect or
a problem by successively asking the question “Why?”. The
number ‘5’ here comes from the anecdotal observation that
five iterations of asking why is usually sufficient enough to
reveal the root cause.
In some cases, it may take more or fewer whys, depending on
the depth of the root cause.
3. Why The Five Whys?
The main benefit of the Five Whys is that it is one of the most
powerful assessment methods of all non-statistical analyses.
It can uncover and trace back to problems that were not very
clear or obvious.
It is simple, and it works.
4. The Benefits of Five Whys
1 Helps identify the root cause of a problem
2 Understand how one process can cause a chain of problems
3 Determine the relationship between different root causes
4 Choose a design you like from the Design Ideas task pane.
5. When Should You Use This Method?
1 For simple to moderately difficult problems
2 More complex problems may require this method in
combination with some others
3 When problems involve human factors or interactions. So any
time human error is involved in the process.
6. How to Complete a Five Whys Root Cause Analysis
1. Begin with a specific problem. What is it that you are having
an issue with? This can also help the team focus on the same
problem.
2. Ask why the problem happened and write the answer down
below the specific problem you listed in step one.
3. Keep asking “why” to each of the successive answers you
write down until you reach the root cause of the problem.
4. Again, this may take more or less than five “why's. Make
sure your team sees eye-to-eye with each of the questions
being answered as well as the final root cause.
7. Key Things to Keep in Mind
Try it yourself with these two simple “planets”:
1 Distinguish causes from symptoms or causal
factors
2 To make sure that you are attributing the correct
answer to each “why”, try working backwards.
(Answer to the “Why?” + “and therefore” + the
Problem Identified for that Question)
3 You can break down your answers as much
as you like. The more the better.
What is a causal factor?
A causal factor can be defined as any “major unplanned, unintended
contributor to an incident (a negative event or undesirable condition), that if
eliminated would have either prevented the occurrence of the incident or
reduced its severity or frequency. Also known as a critical causal factor or
contributing cause.”
A cause influences a process. If the event isn’t related to a causal process, there
can’t be a causal factor. For example, “an alteration of the ball (a mark by a
pen, perhaps) is carried with it as the ball goes through the air. On the other
hand, an alteration of the shadow (insofar as it is possible) will not be
transmitted by the shadow as it moves along.”
4 Answers should always be based on facts
and data
5 Last but not least, assess the process, not
the people.
8. Toyota Five Whys
The Five Whys method was originally developed by Sakichi Toyoda,
the founder of Toyota Industries. This method became widely
used in Toyota Motor Corporation and is still used frequently to this
day. Taiichi Ohno, the architect of the Toyota Production System,
describes the five whys as “the basis of Toyota’s scientific
approach.”
Along with their other “go and see” philosophies, the five whys
method is used along with other famous concepts such as kaizen,
poka-yoke, and jidoka.
9. Five Whys Example
Here’s an example of how this works:
The Root Cause reveals the source of the problem. By coming up with a solution for the
root cause, there is a high chance that all of the whys leading up to the final answer will
naturally get resolved.
10. Five Whys Tools
The simplest way of conducting the Five Whys test is to simply write
it down on a piece of paper. However, the fishbone, or the
Ishikawa diagram, can help during the initial process of identifying
problems. The diagram can reveal problems that may need the five
whys for a deeper look. Then, you can gather all of the root-cause-
effect relationships and evaluate which of them had the greatest
impact on the original problem.
11. More What, why & how’s about 5 Why’s?
Raise your hand &Tell Me what you want to know.
