You are using the ‘5 Whys’ wrong – here’s how to improve.

Best Practice

Text and illustrations by Peter Horvath, Strategy & Service Design Lead at Whitespace

Date: 06 October 2021

The '5 Whys' is a research technique pioneered at Toyota, where you are meant to ask the question “why” repeatedly until you arrive at the root cause of a given problem. Here’s a more detailed demonstration and explanation.

But is “why” really the best question? And will you get to the root cause by the 5th question? No and no. Let me tell you why…

The two flaws with the '5 Whys'

There are two fundamental flaws with the ‘5 Whys’:

  1. You should not ask “why” — for multiple psychological reasons.
  2. And you should have a much clearer roadmap for when to stop than just arriving at your 5th ‘why’.

Flaw #1

The first flaw is that asking “why” may sound simple, but is actually burdened at a cultural, personal, and semantic level.

  • At a cultural level, because there are up to six ways to ask “why” in Japanese (the birthplace of the technique). Whichever “why” was used originally, it came with very different connotations than any western “why”.
  • At a personal level, because the question “Why?”, being asked of us by parents and later by managers has an inherent interrogatory, even blame-attributing nature to it, triggering defense mechanisms.
  • At a semantic level, because (unlike “who”, “what”, “where”, “when”, “how”) the question “why” is past-oriented, motivational, and tends to be abstract and ambiguous.

Flaw #2

And the second flaw is that this technique was developed for a manufacturing process. When improving the design of a service or product for end-users, factual causes are rarely, if ever, the root cause of a problem. There is a much larger human element to it.


The remedy for the '5 Whys'

So how to improve the '5 Whys'? Here are two quick tips:

  • Forget “why” - instead ask “how come”, or use a “what” question to get rid of the accusatory overtone, and get more precise and factual responses.
  • Instead of just asking 5 questions, be very conscious about what level of understanding (page 8) the question is addressing. Are your questions addressing 1- events; 2- trends; 3- structures, or 4- mental models? Only by digging deeper and deeper among these layers will you identify the real root causes.

An example

The classic Toyota example goes like this:

  1. “Why did the robot stop?” — The circuit has overloaded, causing a fuse to blow.
  2. “Why is the circuit overloaded?” — There was insufficient lubrication on the bearings, so they locked up.
  3. “Why was there insufficient lubrication on the bearings?” — The oil pump on the robot is not circulating sufficient oil.
  4. “Why is the pump not circulating sufficient oil?” — The pump intake is clogged with metal shavings.
  5. “Why is the intake clogged with metal shavings?” — Because there is no filter on the pump.

Let’s continue the above inquiry with our newly-gained knowledge:

  1. “How often do welding robots stop due to the problem of missing filters?” —More often than in the past. (level 2: patterns)
  2. Is there an automated process to monitor oil pump or filter health? — There is no automated process, we rely on random checks. (level 3: structures)
  3. Why do you believe the organization omits automated monitoring? — The factory used to operate faultlessly, and I believe we grew complacent. (entering level 4: mental models)

Just 3 additional questions, strategically aimed at going to deeper levels, reveals much more detail and depth to the original problem.

Your ‘5 Whys’ have just gained superpowers! Go use them in your next research project! Or better yet, contact us for a discussion about how Whitespace can help you bring these superpowers and more into your organization.

Super 5 Whys

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