
Definition of 5 Whys:
The 5 Whys typically refers to the
practice of asking, five times, why the failure has occurred in order to get to
the root cause/causes of the problem. There can be more than one cause to a
problem as well. In an organizational context, generally root cause analysis is
carried out by a team of persons related to the problem. No special technique
is required.
An example is in order:
You are on your way home from work
and your car stops:
- Why did your car stop? Because it ran out of gas.
- Why did it run out of gas? Because I didn’t buy any gas on my way to work.
- Why didn’t you buy any gas this morning? Because I didn’t have any money.
- Why didn’t you have any money? Because I lost it all last night in a poker game.
This example should illustrate the
importance of digging down beneath the most proximate cause of the problem.
Failure to determine the root cause assures that you will be treating the
symptoms of the problem instead of its cause, in which case, the disease will
return, that is, you will continue to have the same problems over and over
again.
Also note that the actual numbers of
whys is not important as long as you get to the root cause. One might well ask
why did you lose all your money in the poker game last night?
Here’s another example. The Washington Monument
was disintegrating
- Why? Use of harsh chemicals
- Why? To clean pigeon poop
- Why? so many pigeons? They eat spiders and there are a lot of spiders at monument
- Why? so many spiders? They eat gnats and lots of gnats at monument
- Why? so many gnats? They are attracted to the light at dusk.
Solution: Turn on the lights at a later time.

Asking “Why?” may be a
favorite technique of your 3-year-old child in driving you crazy, but it could
teach you a valuable Six Sigma quality lesson. The 5 Whys is a technique used
in the Analyze phase of the Six Sigma DMAIC (Define, Measure, Analyze, Improve,
Control) methodology. It is a great Six Sigma tool that does not involve
data segmentation, hypothesis testing, regression or other advanced statistical
tools, and in many cases can be completed without a data collection plan.
By repeatedly asking the
question “Why” (five is a good rule of thumb), you can peel away the layers of
symptoms which can lead to the root cause of a problem. Very often the
ostensible reason for a problem will lead you to another question. Although
this technique is called “5 Whys,” you may find that you will need to ask the
question fewer or more times than five before you find the issue related to a
problem.
Benefits
of the 5 Whys
Help identify the root
cause of a problem.
Determine the
relationship between different root causes of a problem.
One of the simplest
tools; easy to complete without statistical analysis.
When
Is 5 Whys Most Useful?
When problems involve
human factors or interactions.
In day-to-day business
life; can be used within or without a Six Sigma project.
How
to Complete the 5 Whys
Write down the specific
problem. Writing the issue helps you formalize the problem and describe it
completely. It also helps a team focus on the same problem.
Ask Why the problem
happens and write the answer down below the problem.
If the answer you just
provided doesn’t identify the root cause of the problem that you wrote down in
Step 1, ask Why again and write that answer down.
Loop back to step 3 until
the team is in agreement that the problem’s root cause is identified. Again,
this may take fewer or more times than five Whys.
5
Whys Examples.
Problem Statement:
Customers are unhappy because they are being shipped products that don’t meet
their specifications.
1. Why
are customers being shipped bad products? – Because manufacturing built
the products to a specification that is different from what the customer and
the sales person agreed to.
2. Why
did manufacturing build the products to a different specification than that of
sales? – Because the sales person expedites work on the shop floor by
calling the head of manufacturing directly to begin work. An error happened
when the specifications were being communicated or written down.
3. Why
does the sales person call the head of manufacturing directly to start work
instead of following the procedure established in the company? – Because
the “start work” form requires the sales director’s approval before work can
begin and slows the manufacturing process (or stops it when the director is out
of the office).
4. Why
does the form contain an approval for the sales director? – Because the
sales director needs to be continually updated on sales for discussions with
the CEO.
In this case only four
Whys were required to find out that a non-value added signature authority is
helping to cause a process breakdown?
Problem Statement: You are on your way home from work and your car stops in the middle of the road.
1. Why
did your car stop? – Because
it ran out of gas.
2. Why
did it run out of gas? – Because I didn’t buy any gas on my way to work.
3. Why
didn’t you buy any gas this morning? – Because I didn’t have any money.
4. Why
didn’t you have any money? – Because I lost it all last night in a poker game.
5. Why
did you lose your money in last night’s poker game? – Because I’m not very
good at “bluffing” when I don’t have a good hand.
As you can see, in both
examples the final Why leads the team to a statement (root cause) that the team
can take action upon. It is much quicker to come up with a system that keeps
the sales director updated on recent sales or teach a person to “bluff” a hand
than it is to try to directly solve the stated problems above without further
investigation.
5 Whys and the Fishbone
Diagram
The 5 Whys can be used
individually or as a part of the fishbone (also known as the cause and effect
or Ishikawa) diagram. The fishbone diagram helps you explore all potential or
real causes that result in a single defect or failure. Once all inputs are
established on the fishbone, you can use the 5 Whys technique to drill down to
the root causes.
Take-away Quotation
“If you don’t ask the
right questions, you don’t get the right answers. A question asked in the right
way often points to its own answer. Asking questions is the ABC of diagnosis.
Only the inquiring mind solves problems.” – Edward Hodnett
The 5 main steps
to the 5 Whys
Step 1: Invite anyone affected by the issue
As soon as the problem or
situation is identified (and all immediate concerns are dealt with), invite
anyone at all on the team who was affected or noticed the issue to be involved
in a 5 Whys meeting. As a remote team, we hold ours via Zoom.
Step 2: Select a 5 Whys master for the meeting
The 5 Whys master will
lead the discussion, ask the 5 whys, and assign responsibility for the
solutions the group comes up with. The rest of those involved will answer those
questions and discuss.
In our experience, anyone
can be a 5 Whys master — there are no special qualifications, and it doesn’t
have to be the leader of the project or the originator of the issue. We’ve also
found that it’s a good idea for the 5 Whys master to take notes for the
meeting, unless he or she would like to assign someone else to this.
Step 3: Ask “why” five times
Dig at least five levels
deep into the issue with five levels of “whys.” This seems like the simplest
part but can in fact get a bit tricky! Getting the right question to start
with, the first why, seems to be the key.
When we conduct our 5
Whys, it can feel natural and almost beneficial to go down all potential paths
and be really comprehensive. However, this can widen the scope of how much
learning and corrective actions need to occur. This is meant to be a ‘lean’
process in which picking one path allows us to perform just the amount of
corrective actions needed to solve a problem.
We often have to tell
ourselves we just need to pick one and go with it. If the same problem seems to
occur again, then we can do another choosing the other route.
Together, we work through
each of those five whys and discover actionable steps that have been or will be
taken.
Step 4: Assign responsibility for solutions
At the end of the
exercise, we go through each why question-and-answer pairing and come up with
five related “corrective actions” that we all agree on. The master assigns
responsibility for the solutions to various participants in the discussion.
Step 5: Email the whole team the results
After each 5 Whys
process, someone involved in the meeting will write down what was discussed in
the clearest, plainest language as possible.
Then we add it to a Paper folder and—in one of the most important steps
of the whole process—email the whole team with the results.
This makes sense to do,
and not just for a company like Buffer that focuses on transparency. It’s super
useful for everyone on your team to stay in the loop and understand any steps
you’re taking as the result of a 5 Whys.
Eric Ries explains why the email is so important:
The advantage of sharing
this information widely is that it gives everyone insight into the kinds of
problems the team is facing, but also insight into how those problems are being
tackled. And if the analysis is airtight, it makes it pretty easy for everyone
to understand why the team is taking some time out to invest in problem
prevention instead of new features. If, on the other hand, it ignites a
firestorm – that’s good news too. Now you know you have a problem: either the
analysis is not airtight, and you need to do it over again, or your company
doesn’t understand why what you’re doing is important. Figure out which of
these situations you’re in, and fix it.
Put it all together and
the process looks like this:
Some real-life 5 Whys
examples
To take the 5 Whys from
theoretical to actual, here’s a look at a few moments in Buffer’s history that
have called for a 5 Whys meeting.
In early 2014, we had a
brief system wide outage. Here’s a look at the 5 Whys the team conducted:

Buffer 5 whys example
And the corrective
actions that resulted:

Buffer 5 whys corrective
actions
Here’s an example from
the customer happiness world. One of our Happiness Heroes wanted to understand
how he might have handled a customer’s problem better, so he performed a
modified 5 Whys as a reflection and shared it with the team.
5 whys support

I have learned so much
from viewing these examples and being part of 5 Whys processes. It’s been great
to develop a habit of reflecting anytime something unexpected happens and
taking incremental steps so that we change what happens the next time around.
The 5 Whys in daily life
Although the 5 Whys is
most widely used for manufacturing/development use, I’ve found that it is also
quite applicable to daily life in any situation where one might seek deeper
understanding—of a problem, a challenge or even a motivation behind an action.
This quick graphic from
Start of Happiness provides a great example:

5-Whys-Problem-Solving
Ever since learning about
the 5 Whys, I find myself asking “why?” a lot more often.





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