I’m starting a new tradition here, after one of my role models – Fred Wilson. He used to write an MBA Monday section for his blog, AVC, which was great. I’ve decided to write about mental models, heuristics, and biases.
The “Five Why’s” was one of the first mental models I came across, and one that has helped me tremendously in jobs I felt out of my element in. The five why technique enables you to get to a root cause by tracing the causes of problems back to where they began. When I first started working in tech, I relied on this constantly, since I didn’t understand the tech jargon enough to know what “The API is broken” meant, but didn’t want to leave the problem unresolved there. Wikipedia has a great example that I’ll post below:
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The vehicle will not start. (the problem)
Why? – The battery is dead. (first why)
Why? – The alternator is not functioning. (second why)
Why? – The alternator belt has broken. (third why)
Why? – The alternator belt was well beyond its useful service life and not replaced. (fourth why)
Why? – The vehicle was not maintained according to the recommended service schedule. (fifth why, a root cause)
The questioning for this example could be taken further to a sixth, seventh, or higher level, but five iterations of asking why is generally sufficient to get to a root cause. The key is to encourage the trouble-shooter to avoid assumptions and logic traps and instead trace the chain of causality in direct increments from the effect through any layers of abstraction to a root cause that still has some connection to the original problem. Note that, in this example, the fifth why suggests a broken process or an alterable behaviour, which is indicative of reaching the root-cause level.
It is interesting to note that the last answer points to a process. This is one of the most important aspects in the 5 Why approach – the real root cause should point toward a process that is not working well or does not exist. Untrained facilitators will often observe that answers seem to point towards classical answers such as not enough time, not enough investments, or not enough manpower. These answers may be true, but they are out of our control. Therefore, instead of asking the question why?, ask why did the process fail?
A key phrase to keep in mind in any 5 Why exercise is “people do not fail, processes do”.
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The last point on processes is one of the most important, and a key to the whole model. If you start using this model and repeatedly run into the “I didn’t have enough time,” answer, then you know there is a broken process somewhere. You need to figure out what the process is that is broken, and go to work fixing that. This helps avoid finger pointing and discouraging results of the model.