Fishing for the Root Cause

The Fishbone or Cause and Effect diagram is a model to help you identify and manage the root cause of an issue or incident you are concerned about. It is also called the Ishikawa diagram after its creator Kaoru Ishikawa, an icon, in Japanese quality control. The diagram starts at the 'fish head', where the problem being studied or to be solved is stated. The fish's body contains branches of the possible areas that could have contributed to the problem at the 'fish head'. Sub-branches then further drill down in detail (within that branch) into more specific factors contributing to the failure. The example below shows a diagram with 4 branches and 2 levels of causes but there could be more or fewer branches and levels depending on your scenario.

To help you with the application of the diagram, there is an iterative interrogative technique known as Five Whys. The goal is to identify the underlying root causes by repeating the question 'Why' five times to the problem. Here is a simple supply chain example:

Problem: There is a customer complaint

1. They could not find what they wanted

2. The item they wanted was out of stock

3. There was a failure of the replenishment model

4. The data going into the model is inaccurate

5. There is insufficient control of data entry

• A suggested solution could be to improve data entry controls and make the process of data entry easier.

This technique forces you to think deeply about the potential areas causing your problem. Knowing the root cause(s) is critical in solving the problem. Your solution may not be successful if it doesn't address the root cause. Even if it does improve the problem, it would be a surface-level solution that will likely require ineffective and repeated application. So if your problem persists after you have addressed it, your solution likely only addressed the symptom and not the cause.

A business mentor once told me that the person who knows 'why' something needs to be done will always be the boss of the person who knows 'how' to do that something. I think this method of thinking can be applied not only in business and in supply chain management, but in all areas of life. Knowing why things are will help provide the empathy and vision desperately needed to address the serious problems we face today.