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5 Whys

What is 5 whys

One of the most common approaches to arrive at the root cause of a problem. The process is to ask "why" until we arrive at the root cause . 5 is a guideline and not restrictive, you could more or less than 5.

How to do 5 whys

  • The process is simple, ask why until the team / you are comfortable that we have arrived at the root cause OR there is no more logical answer possible

  • Do it with the team ( relevant responsible parties - preferably doers)

  • All brainstorming rules apply ( see brainstorming )
    It can get irritating when only one person questions and one answers - be prepared for it, try and rotate, contribute, keep it friendly tone

  • You can stop to investigate/check facts/ get to another expert

  • Its also good to check the whys arrived at confirmed by parties other than the group

When to use 5 whys

  • To arrive at a root cause

  • To choose between options

Variations

  • Ask "what if" 

  • Ask "so what"

Example of 5 whys
5 why.png

  • As you go thru the example – see that you may need to work all “countermeasures” and not just the first or last

  • Some are immediate / in control of the project team and some not – treat them accordingly

  • To completely remove the root cause, you may need to work with teams/leaders outside your influence, work with your project sponsor to influence them

  • The above example is simpler, with each why showing only one cause …. It will happen that “ why” may lead to multiple answers, choose the most relevant tree to proceed

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