Five Whys (5 Whys or sometimes known as 5Y) is a simple but powerful tool for cutting quickly through the outward symptoms of a problem to reveal its underlying causes. The method is remarkably simple: when a problem occurs, you drill down to its root cause by asking "Why?" five times. Then, when a counter-measure becomes apparent, you follow it through to prevent the issue from recurring. The 5 Whys technique is most effective when the answers come from people who have hands-on experience of the process or problem in question. The 5 Whys uses "counter-measures," rather than "solutions." A counter-measure is an action or set of actions that seeks to prevent the problem from arising again, while a solution may just seek to deal with the symptom. As such, counter-measures are more robust, and will more likely prevent the problem from recurring.
- Definition - What is the Five Whys technique? Mindtools