5 Why analysis is a simple tool which identifies the root cause of a problem by repeatedly asking the question “Why”. It is commonly accepted that you can identify the root cause by asking “why” five times, although this is not a strict limit. The objective is to peel away the layers of symptoms leading to the true root cause of a problem. Figure 11 shows a simple 5 why analysis for a vehicle not being able to start:
Figure 11: 5 Why Analysis