Skip to content

“Five Whys” Goes Both Ways

2015 July 22
by Nayan Hajratwala

You’ve found a problem:

“Our test environment is down all the time”

You want to make sure you fix it as well as prevent it from happening again.

A popular approach is to use the Five Whys root cause analysis technique. People who are new to Five Whys often run into a couple problems right away.

Up or down the stack

The first problem is which kind of “why question” to ask. Given the problem above, you could ask the following questions:

  1. Why does/did this happen?
  2. Why does this matter?

Both are valid questions, but they each travel in different directions. Repeatedly asking the first question allows you to get down closer to the root cause(s) of the problem:

down_the_stack

 

Repeatedly asking the second question will send you up to find the actual harm that the problem is causing:

up_the_stack

The item that is your initial problem is very likely the cause of someone else’s problem.

It can be helpful to traverse in both directions when doing analysis, but in general, if you assume you’ve identified a valid problem, focusing on “Why did this happen?” will be the most beneficial.

How many whys?

The second thing that people get hung up on is the number of whys. This one’s pretty simple. It’s just a guideline, so keep askin’ till you can’t ask no more. It may be 3, it may be 10, but chances are that if you haven’t gone at least 5 whys deep, you haven’t found the root cause. Keep thinking!