Some thoughts on “5 Whys”

The “5” is a reminder to avoid shallow attribution

Service stopped working because SSL certificate expired. “Well, we can’t stop SSL certificates from expiring, I guess there’s nothing we can do!”
People have a general tendency for shallow attribution
Service stopped working. Why? We didn’t renew the SSL certificate before it expired. Why? We didn’t know that the SSL certificate was about to expire. Why? …
5 Whys is a reminder to go beyond shallow attribution

“5” is a heuristic not a fixed number

“5” is not a fixed number but more a heuristic

5 Whys, not 5 Whos

“Who” focuses only on personal vs other factors

“How” seems clearer than “Why”

“Why” can be confused for asking about motivation; “How” only implies mechanism
“Why” can be confused for asking about motivation

But there’s usually more than one root cause!

There is no assumption that there is a single root cause. It’s not called “single root cause analysis”.

“Should we also explore why it took so long to detect the problem?” “Nah, I’m pretty sure we’re not supposed to think for ourselves with 5 Whys.”
It’s not “single root cause analysis”

To reliably interrupt a mechanism, intervene at multiple points, not just the “root cause”

Diagram showing interventions at multiple points in a 5 Whys chain
Intervene at multiple points

You don’t actually need to address every contributing factor

We’re seeing more random blow-ups over small things. Explore factors we have influence and leverage. Don’t explore factors where we have limited influence.
You don’t actually need (or want) to explore every contributing factor

But it’s too simple to work for complex problems!

Every organisation has problems at different levels

The least number are sophisticated, complex problems. Somewhere in the middle are complicated problems. The largest number are day-to-day, simple problems.
Distribution of problems in most organisations

Use the simplest method that is useful (including fitting within the time you have available)

“5 Whys most applicable here” pointing to the day-to-day, simple problems
5 Whys is most applicable to day-to-day simple problems
Service stopped working. Why? SSL certificate expired. “Wait! Before we go further, let me set up an anthropological study…”
More sophisticated approaches are not intended for simple problems

To learn more

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Senior Manager Product Engineering at Grainger. Extreme Programming, Agile, Lean guy. Ex-Spotify, ex-ThoughtWorks, ex-CruiseControl

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Jason Yip

Senior Manager Product Engineering at Grainger. Extreme Programming, Agile, Lean guy. Ex-Spotify, ex-ThoughtWorks, ex-CruiseControl