Why – 5 Times to identify root cause

Asking "why" or "why is this so" may be a favorite question for small children who want to know more about the contents of the objects in this world. But the technique question Why or why this repetitive can be a powerful Technique in solving a problem with finding the root cause of the problem is concerned. Engineering question "Why" this does not require an analysis of the techniques tricky as hypotheses, regression or correlation. But this technique requires an approach to the principle of the flow of "logic" in the sharp digging up to the root of the problem.


By repeatedly asking "Why" or "Why", we can peel the layers one by one until you get to the core issues or the root of the problems that we face. In General, a reason to be the answer to the question "Why" it will raise questions of "why" next so there will be an awful lot of arising questions "why" that will even surpass the 5 questions "why".

Technique 5 Rev. was introducing by Toyoda and was used by Toyota Motor Corporation of Japan. To develop his company's Manufacturing Methodology. As said by Taiichi Ohno (architect of the Toyota production system), by repeating the questions "Why" or "why" five times, the nature of a problem and also the solution will become increasingly clear.

The advantages of the technique of 5 Rev. (5 why)

• Assist in updating the identify the root cause of a problem


• Determine the relationship between root-the root cause of a problem


• One of the tools of problem solving is easiest to use

Example 5 Why analysis techniques (5 why)

The problem: the invention of the delivery model to the wrong customers

1. 1: why is there a wrong delivery model to customers?
   Because an error occurred in retrieving by logistic staff


2. 2: why is there an error in the uptake by staff of logistics?
   Because of the Logistics staff does not scan the barcode on a Box that will be sent.


3. 3: why Logistics Staffs not scan barcode system on a Box that will be delivered?
   Because the computer used for the Barcode Scanner is broken at the moment


4. 4: why is the computer used for the Barcode scanner is broken?
   Because the computer used to sudden death scanners


5. 5: Why computers are used for these scanners dies suddenly?
   Because the power supply was suddenly dead

From questions 5 Rev., obtains that the demise of the power supply is the root cause of the onset of problems wrong delivery. Therefore, the necessary precautions so that the same thing does not happen again.

Examples of actions that can be taken for example by adding a Backup Power Supply or UPS on the computer. So that the demise of the electric flow occurs when a computer scanner. That can still be used or at least still has time to do the shutdown on a computer scanner.