How to Coach Yourself and Others Essential Knowledge For Coaching | Page 309

4.18 ROOT CAUSE ANALYSIS
The Five Whys (or 5 Whys, or 5Y) technique is especially popular
in manufacturing, where the main concern is often productivity - maximizing production rate and minimizing rejects. I've heard
many Six Sigma and Lean practitioners talk about this as one of
their favourite tools. I can understand why, too... it's easy to
remember, simple to apply, and gets deeper than traditional
problem solving. However, it also contains some traps.
In summary, you simply ask "why did this occur", and after you
answer that, you ask "why did that occur", and so on. You keep
going until you get to something fundamental, or until you reach
something that's completely outside your control. A rule of
thumb seems to be that 5 iterations is a reasonable average, but
this is not a hard rule... it may take only 3 levels of "why", or you
may still be asking "why" 5 weeks from now. It just depends on
the problem.
Now, can you spot the problems in the procedure summarized
above? I can think of a few, but there are two that I think are
really important. First, there is the assumption that a single
cause, at each level of "why", is sufficient to explain the effect in
question. This is rarely the case! Most often, you need a set of
jointly sufficient causes to create any single effect. Second, what
if one of your "why" answers is wrong? Maybe your answer was
possible, but what if the actual cause (i.e., set of causes) was
something else entirely? Even worse, what if your seemingly
plausible answer was completely out to lunch?
One of the advantages of the 5 Whys is that it gets you to fairly
deep, underlying causes. A major disadvantage is that if you
make a mistake answering just one "why" question, your entire
analysis gets thrown off. Even worse, the earlier your mistake in
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