The 5-Why’s technique of getting to the root cause of an outcome is effective and very simple. It may take 4 or 6 — but 5 is the general rule of thumb.
That said, because it is a simplistic method, that can also lead to premature conclusions or settling on one root cause when there can be several. In any case, this discipline provides insights that should be useful.
Note: This can be used for both negative (Problem) and positive (possible best practice) outcomes.