Use 5 Sequential “Whys,” not 5 Random Ones, to Dig Deeper Toward a Root Cause


I had an opportunity to coach somebody, remotely, the other day on the Lean problem-solving process called “the 5 Whys.”

The person presented a situation like this — I'm changing the details and making up a scenario.

The 5 Whys she gave were along these lines:

  • Why are patients waiting so long for discharge?
  • Why do we wait so long for each consulting physician to get back to us about discharging the patient?
  • Why do we wait for the nurse to be available to transport the patient?
  • Why aren't transporters available?
  • Why do we not get enough advance notice about discharge instructions?

My feedback was that they had asked 5 different and related “why?” questions but they hadn't really followed the “5 Whys” process.

The 5 Whys starts with a problem statement and then digs deeper rather than just asking related questions.

The format should be more like this:

Problem Statement: Patients wait too long to be discharged

  • Why? Statement that answers the question
  • Why is that? New statement
  • Well why is that? New statement
  • Why is that? New statement — possibly the root cause

There's no specific magic as to why you get the root cause after 3 whys or 6 whys.

Here is a good example from an article published by a pharmacy industry group, the American Society of Health-System Pharmacists.

Problem: delays in medication turnaround time.

  • Why? Need to wait for deliveries to unit.
  • Why? I.V. preparation of first doses takes too long.
  • Why? Time is wasted time in work area.
  • Why? Excessive walking is required.
  • Why? The work area layout is inefficient.

Of the five questions, the primary root cause is identified as being the work area layout.

Do you see how those questions were sequential? The chain of questions might branch off — for example, why does I.V. preparation of first doses take too long? There might be two valid answers you want to dig into. It might form more of a tree than a vertical stick:

That's more like a real root cause analysis.

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Mark Graban
Mark Graban is an internationally-recognized consultant, author, and professional speaker, and podcaster with experience in healthcare, manufacturing, and startups. Mark's new book is The Mistakes That Make Us: Cultivating a Culture of Learning and Innovation. He is also the author of Measures of Success: React Less, Lead Better, Improve More, the Shingo Award-winning books Lean Hospitals and Healthcare Kaizen, and the anthology Practicing Lean. Mark is also a Senior Advisor to the technology company KaiNexus.


  1. Wow, whoever was teaching these people should have their lean license revoked.

    5 Whys takes 5 minutes to teach (although they still should get that part right) and a lifetime to master.

    Some time ago someone asked me "if I could only pick one lean tool, what would it be?" Of course it's a stupid question because why would I have to be in that situation. But if I was, I would choose 5 Whys. I think if you get this right and master it in the organization, you eventually will find your way to everything else.

  2. Mark,

    How do you know when you've found the root cause and simply not unmasked another symptom? In the pharmacy example, the root cause was identifed as inefficient layout. But one could ask why again and discover the layout is inefficent because there's not enough space in the work area, so materials and supplies are placed anywhere that space is available.


  3. Jamie,
    Unfortunately as we all know there is no Lean License…. With so many people looking for jobs as Lean Consultants, the employers are treating it as a commodity. I guess in this case they got one of the defective nuts in the nut commodity purchase.


  4. To Jamie and Lester-

    To be fair to everyone involved, the woman I was coaching was pretty much self taught from her reading and research. I didn't mean to imply there was a "bad consultant" involved.

    To Jason M –

    You raise a good question. You could continue down a path of "why is the work area layout inefficient?"

    – The space was not designed properly — why?
    – The architects dictated the layout — why?
    – The laboratory did not understand its process well enough and did not feel comfortable pushing back — why?
    – There is a lack of process and systems engineering education in healthcare

    You pretty quickly get to things that are only solvable over the years or decades time horizons.

    I think you stop when you get to a point where you can take fairly direct action. Layout is inefficient — what can we move this month?

    If the laboratory doesn't have flexible furniture, then it becomes a pretty major project to A) change the layout and B) change it in a way so that it's flexible for the future.

  5. The other day i was thinking about the five why's. I realised two things:
    (1) you should act on all the effects you find as well as the root cause. (How stupid of me to think otherwise, but as I'm in a non manufacturing business, i don't actually see the oil spilled and it took me some time to see the 'spilled administrative oil')
    (2) With some help form Mark Grabhan ( The root cause is the last answer that gives a cause on which you can define a countermeasure.

    if you've useful comments place them here or post them on twitter with a #lean sign.


  6. Mark,
    I am glad I did not have to try to figure Lean out without a good teacher to hold our hand. That would have been tough, and possibly counterproductive.

    For the 5 why's, I was always taught to have countermeasures for each step. If oil is on the floor, the countermeasure is to mop it up while you also look for the root cause. Our 5 why matrix therefore had three columns.

  7. A couple of thoughts on the 5 whys –

    First, this is one of those tools that was kicking around "TQM" and "QIP" (etc., etc.) before Womack ever uttered the word "LEAN". Our (flavor-of-the-year-style) TQM deployment in the 90s actually did a pretty good job of teaching the "5 whys" and even put them on fishbones (Ishikawa diagrams, cause and effect analysis) with the 4 Ms we learn from Toyota today – men, materials, methods and machines – as the main "bones". Don't misunderstand, this is not a critique of TPS or Lean, just acknowledging that "5 whys" analysis is one of the tools that penetrated American consciousness pre-Womack.

    Second, (and more useful, probably – thanks for sticking with me!) is an effective way to audit a "5 why" analysis: Walk it backward, from bottom to top, with the word "therefore" substituted for "why". You will frequently turn up logical flaws in the chain of cause and effect. These can really get in the way of effective problem solving.



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