Some thoughts on “5 Whys”

Jason Yip
4 min readJun 26, 2022

The “5” is a reminder to avoid shallow attribution

When faced with a problem, there’s a general tendency for people to only consider the immediate contributing factors.

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

The “5” in “5 Whys” is a reminder to go beyond shallow attribution and keep exploring underlying causes.

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

In practice, the number of whys can be less or more than 5. Because of the tendency to be shallow, I’d still suggest thinking about it more if it ends up being less than 5.

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

5 Whys, not 5 Whos

The use of “why” is to remind us not to default to blaming people, especially their motivation (aka fundamental attribution error), and consider broader factors for why something happened.

“Who” focuses only on personal vs other factors

See also Six Sources of Influence.

“How” seems clearer than “Why”

The purpose of root cause analysis is to understand mechanism(s) to allow us to come up with better ideas for how to intervene. “How” expresses this more clearly than “Why”.

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

See also “Why” is about purpose; “How” is about mechanism.

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”.

The idea is that you’re exploring a single promising factor with 5 Whys. This does not mean you won’t…

Jason Yip

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