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Root causes: what are they good for?

1 March 2015

David Rozental

Everybody learns lessons. Everybody wants to improve their lesson learning.

Researches and lesson learning were always intertwined with Knowledge Management. The connection between lessons, organizational learning, organizational memory and learning from past experiences create this tight relationship. In today's market there are several lesson learning methodologies: the drilling method, the increasingly popular AAR method as well as many other methods and versions. All methods share the same purposes:

  • To reproduce successes.

  • To prevent recurrence of mistakes.

  • To avoid reinventing the wheel.

The common denominator of everyone involved in this field is the fact that regardless what method they choose, it's always important to search for the root causes. During the lessons learning activity, the team members should invest in finding the causes for the gap between the organization's predictions and reality. It is customary to attempt to reach the root causes at this point. Root causes are defined as the basic causes that led to the situation debriefed. Preventing the root causes would in effect prevent the whole situation from happening.

So, what's the problem?

When a team debriefs an event and attempts to understand its causes, there is usually a tendency to halt at a very high level of answers. This abrupt stop at a relatively superficial and trivial level will usually yield basic and trivial lessons and produce corrective activities and not the desired preventive activities.

Typical causes that are discovered in debriefs include:

  • Lack of training.

  • Human error factor.

  • A lack of procedures.

These factors are usually just a superficial symptom of a larger systematic problem. Therefore, we must search deeper and reach the root cause.

There are several methods and approaches for analyzing root causes, the most popular one is the good old "5 whys" method. This simple method assists us in "peeling away the layers" of symptoms and reach the root cause. It consists of asking "why?" five times. The method was developed by Taichi Ono, a Japanese businessman who is a key figure in the LEAN field. Ono is considered the founder of the Toyota Production System.

It's important to emphasize that 5 is not a 'holy number'. We must ask the number of questions required in order to discover the root cause, whether 5, 6, 8 or 3. The 5 whys method assists us in finding the problems in the process, and 5 levels as a rule of thumb, usually brings us to the root cause.

When does one eventually stop asking?

When one reaches a factor beyond one's control or when a factor beyond the sequence of facts and symptoms has been detected. We have then reached the root factor.


What happened?         The car wouldn't start.

Why?                           The battery ran out.

Why?                           The alternator malfunctioned.

Why?                           The alternator belt tore.

Why?                           The alternator was worn.

Why?                           The car wasn't taken care of in time.

The car care is a diversion from the sequence of facts and is a first reference to a process. We have reached the root cause.


To conclude, peeling the events away and reaching the root causes is a perquisite for quality lessons learning. Utilizing the 5 whys method or others can be indeed helpful.

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