Skip to content
femme utilisant la méthode des cinq pourquoi au sein d’une usine pour identifier la cause profonde d’un problème.

Problem-solving is the bread and butter of most factories today, but not all organisations solve their problems the same way.

Today, we dissect the operating principles behind the 5 Whys method, exploring its advantages, use cases, and relevance.

What do the 5 Whys mean?

By definition, 5 Whys is a problem-solving technique that uses Root Cause Analysis (RCA) to understand the problem in detail and solve it permanently. It’s considered one of the most effective problem-solving techniques in lean management, and it works best to solve simple problems.

This method was developed by Sakichi Toyoda, founder of Toyota, and incorporated into the Toyota Production System (TPS).

The 5 Whys work best to solve relatively simple issues, as anything too complex will need more robust problem-solving tools such as 8D, Cause Effect Analysis, or QRQC.

How do the 5 Whys work?

This method is relatively straightforward. All you have to do is identify the problem and then ask why five times.

Sometimes, you might find the root cause before you reach your fourth line of inquiry.

Sometimes, you might have to ask why a few more times to reach the root cause.

To make the 5 Whys method really successful, there is a process you need to follow, and it goes like this:

Step 1 — Create a team

The more relevant people you include to find a solution to the problem, the faster and more effective the resolution will be.

When you’ve decided who will be part of your team, you should appoint a leader to guide the process and keep everyone on track.

This person is known as the 5 Whys Master.

Step 2— Identify the problem

The problem needs to be identified and clarified beyond any reasonable doubt. Your team should define the problem and explain it in a specific statement. 

This keeps everyone focused on the problem, giving them a concise account of the situation.

Step 3 — Ask Why? five times

The first Why? is on your team.

The other four, on your 5 Whys Master.

Essentially, the team starts asking the first question, and then the 5 Whys Master leads the process through the rest of the questions.

Sometimes, you might need more than five whys to solve the issue.

Sometimes, you might need less.

However long it takes, you need to reach the root cause of the issue, which will always be linked to a management issue or a design flaw.

STEP 4 — Correct the problem

When the problem is identified, your team discusses actions or countermeasures to solve the issue.

The 5 Whys Master will then decide who does what, delegating responsibility among the team members.

STEP 5 — Keep track of your results & share them

Monitoring helps you see if the countermeasures you take to solve the issue are working.

It also gives you great insight into what you’re doing right, and what could be done better.

You also need to share your findings so that everybody can access them and learn from the process.

To make sure you’re using the 5 Whys method to its fullest extent, you need to make sure that you/your team:

  • Know when to stop asking Why → when the answers you’re getting are no longer useful or don’t bring anything else to the process, you need to stop asking further whys and take another approach instead.
  • Address the root cause(s)  → finding the root cause it’s great, but not enough. Once you find it, you need to make sure you’re taking the appropriate measures to fix the issue and prevent it from happening again.
  • Monitor your measures → once you take measures to address the issue, it’s fundamental that you monitor how the measures impact the issue. Are they effective? Could they be even more effective? When you monitor how your measures are performing, you’ll be able to solve the root cause faster and more efficiently.
  • Share your results → keeping your results a secret helps nobody. When you find the root cause, you address it, and you fix it, you need to share your results with everybody, so they can learn from it. Even when the root cause isn’t fixed, you need to share your results to keep everybody on track regarding the issue and its current status.

5 Whys in real life

Here’s what a 5 Whys method looks like in real life:

5 Whys Analysis Graph

In this particular instance, after finding the root cause, we then come up with a solution. In this case, it could be to make sure we train the workers on the standards regarding changing the pipes.

This example shows how easy and cost-effective it is to set up this problem-solving method to find the root cause of a problem in your factory.

Advantages of the 5 Whys methodology

This method brings with it a good number of advantages, and it might be exactly what you need to implement in your factory, some of which are: 

  • It helps your teams find, understand, and correct the root cause of the problem
  • It fosters teamwork
  • It’s very easy and flexible to implement
  • You can use it alongside other problem-solving methods, such as Root Cause Analysis or Six Sigma
  • It can be templated — just create a set structure and prompts that can be used whenever this method needs to come into play

mlean® and the 5 Whys method

The 5 Whys method is a great problem-solving technique that helps you find the root cause of an issue and take measures to correct it quickly and efficiently.

But sometimes, this method alone isn’t enough to solve your problem.

Our mlean® Production System includes a wide range of problem-solving methods to ensure your issues are always dealt with using the right tools.

Our software is the most complete toolkit for digital industrial operations, integrating a variety of lean philosophies and processes like Kaizen or Hoshin Kanri.

mPS digitalises your factory processes, increases your workers’ safety and motivation, and increases revenue.

Book a demo and see for yourself!

Request a Demo Today

Duis aute irure dolor in reprehenderit in voluptate

Play Video