Root Cause Analysis
A plant manager walks past the assembly line and notices a puddle of water on the floor. Knowing that the water is a safety hazard, he asks the supervisor to have someone get a mop and clean up the puddle. The plant manager is proud of himself for “fixing” a potential safety problem. The supervisor, however, is suspicious. He is not sure why the puddle is there. It wasn’t there yesterday. He wonders what caused the puddle to be there today. Therefore, he looks for a root cause by asking ‘why?’ He discovers that the water puddle is caused by a leak in an overhead pipe. He asks ‘why’ again, and discovers that the pipe is leaking because the water pressure is set too high. He asks ‘why?’ again and discovers that the water pressure valve is faulty. He asks ‘why?’ again, and does not get a further answer. The faulty valve is the root cause of the problem. So, the valve is replaced, which solves the symptom of water on the factory floor. Root cause analysis is a way to identify the ultimate ...