5-Why – Getting to the Root Cause

5-Why solutions for each Why

Download 5-Why templates at the bottom of this page (one PPT, one Excel)

The 5-Why approach continues to ask “Why?” when a problem occurs, until the root cause is arrived at.

The number five is a rule of thumb for the number of Why’s required to reach the root cause, but asking “Why?” five times versus three, four, or six times is not a rigid requirement.

Two Companies, Two Responses

It is human nature to be as efficient as possible in everything we do, and this wonderful trait helps us in most situations.

But our quest for efficiency can result in a shallow problem solving approach, and the result is a constant hustle that makes us feel like heroes in the moment, but does not provide any lasting value. This is why we use 5-Why.

The low-value hustle can paralyze companies and individuals when new challenges and competitive pressures arise. The result is slower processes (due to things going wrong on a regular basis) and increased costs, which customers always notice. Oh yes and the biggest impact of all: an exhausted and frustrated workforce that “just can’t handle one more thing.”

So while 5-Why is a very simple tool that can be understood in a few seconds, its implementation is far more daunting and requires strong leadership and personal discipline on everyone’s part.

Jack Rabbit Industries

Looking at the example above, the wrong item was shipped to a customer due to the product being mislabeled. Jack Rabbit Industries (JRI) like many organizations would take the complaint at face value and ship a replacement product. Done.

“We shipped the replacement product the same day that we got the complaint. Great work, Team!” Sadly, JRI assumed that one of their stock pickers was having a bad day and pulled the wrong product. “It was a one-off.”

It took several weeks for the problem to escalate (through more occurrences with more customers) enough to get JRI’s real attention. At this point a lot of damage had been done:

  • Three very upset customers
  • A worn-out customer service team
  • Lots of mislabeled product in the pipeline
  • Two of JRI’s best people being pulled away from their projects for six weeks to handle the fallout

Lean Enterprises Inc.

Lean Enterprises on the other hand asked, “How could this happen?,” and began investigating by asking the customer for a picture of what was received, at which point they realized that the product had been mislabeled.

“We could have easily assumed a stock picking error, but the pickers were doing their jobs properly, matching the product label with the order.”

Lean Enterprises then dug into why the product was mislabeled and found that the labels were being batch processed, and there were products and labels lying around the labeling area. It was easy to see how a product could become mislabeled.

Lean Enterprises ended up solving the problem by implementing single-piece-flow in the labeling area. One product and one label are presented to the labeling person at a time and the chaotic unlabeled product and label situation exists no more.

As an added bonus, the single piece flow solution increased the labeling capacity by 32%, since the employees were no longer wasting time searching through inventory.

Lean enterprises solved the problem in two days and ended up with a more efficient process as a bonus.

Reporting Format

The above example shows a typical 5-Why format for narrow problem statements where one cause-path exists.  For broader problem statements where two or more causes are involved, the following format is effective –

This format is also very useful for explaining the causes behind the top bars on a Pareto chart, as in the case above where a team has collected data and built a Pareto chart on top-level reasons for downtime.  Instead of simply showing a Pareto chart with no further insight into each Pareto bar, the team selects the top two items (material shortages and downtime on machine ABC) and uses the 5-Why format to explore the root causes of each.

Noting Actions Directly on the Document

Remember that 5-Why exercises are only useful when actions come from the meeting.   Take time to document those actions/next steps with the team, and then follow up to ensure that they are implemented.  Recording action items to the 5-Why document itself is a great practice, as shown below.  Don’t forget to agree on the action owners and estimated timing!

Leading a Root Cause Analysis Meeting

1.  Schedule the Meeting

Schedule a time for the 5-Why discussion, and invite individuals who know about the product and/or process at hand.  Your goal should be to run an efficient meeting and complete the 5-why in one session, no more than an hour long.   5-Why is not meant to be a lengthy exercise.

2.  Plan for a Successful Outcome

Clearly state the problem and desired outcome in advance of the meeting, via the meeting notice, email, etc..  An example of this would be:  “Complete a 5-Why analysis on problem ABC and understand next steps for further investigation / corrective action.” Have an easel pad or large dry-erase board in the meeting room, and have the problem statement and 5 Why column headers already documented before the attendees show up.

3.  Run a Successful Meeting

Remember that the success of your meeting will determine attendance at your future meetings!  You want to have a reputation for holding productive meetings, being highly respectful of attendees while keeping the meeting on track to achieve desired outcomes.

Take a couple of minutes at the start of the meeting and explain that 5-Why is a way to document root causes, showing an example (use the Powerpoint file above if you don’t have a more relevant example from your company).

Take another couple of minutes to clearly state the problem, and make sure everyone agrees with the problem statement.  The more specific the problem statement, the better.

4. Agree on Follow-Up Actions / Next Steps

Take time to document those actions/next steps with the team, and then follow up to ensure those actions are implemented.


5-Why is useful for straightforward problems with systemic causes like the case noted above, where poor preventive maintenance is the systemic cause for unplanned equipment downtime.

In cases when the root cause is not readily apparent, 5-Why by itself will not solve the problem.

For example, if a toy manufacturer needs to improve color consistency in a product, they will need to understand which factors influence color the most (otherwise they might not need a Six Sigma project to begin with).  In cases like this, structured analysis methods like multi-vari, correlation analysis, and DOE may be necessary to actually learn the physical relationships between the input variables (process settings, raw materials, etc.) and output variables (in this case, color).  If your team is attacking a number of product variation challenges, then read Keki Bhote’s World Class Quality for a highly effective approach.

Templates and Related Links

Also visit the 5-Why Training PPT page for a complete training page.

**Update – we recently added the best 5-Why template, and dedicated a page to it with screenshots, etc.