| Fishbone Diagrams - Why and How |
By:
Steve Wilheir |
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The identification of the reason for an event increases the chance that the event can be caused or prevented in the future. The process of finding the fundamental reason why some event or defect occurred is called Root Cause Analysis.
There are a lot of tools that have been made for root cause analysis to function. Several tools are the Pareto chart, the failure mode and effects analysis (also known as FMEA), as well as the fishbone diagram. Although every one of these tools are worthwhile, the fishbone diagram will be examined more intensely.
The fishbone diagram has few other names such as the cause and effect diagram, 5-Whys, and the why-why diagram. These names are appropriate because this tool seeks to find the reasons why a particular event (the effect) was caused.
By working from the end after figuring out the effect is the universal algorithm for coming up with a hypothesis. Usually, this is the incident or problem someone is trying to identify. Determining cause and effect is after that. If you ask yourself "What is causing this?", you can come up with many different responses and you should compose those in catalog form. Upon the determination of the answer, you ask yourself again.
For every cause, the "why" question is asked till no more answers could be generated or till five generations have been completed (hence the 5 -Whys. Due to it,the general shape of this diagram looks similar to a horizontal tree. At the far right the original event(the effect) is listed. Then a horizontal line is drawn towards the left. From the horizontal line,the answers the "why" questions are listed. Then the reasons for those answers are branched off. In most of the cases,the branches are a little bit slanted creating a look of a fishbone.
A company desires to cut its costs for the quarter. They do not order tools. The workers then do not have the tools they need to make the product. Without the proper tools, the workers take longer to complete their work. This results in higher wages so the price of the product must be raised. At a higher price, the customer refuses to buy the product. This is an example of the 5-why chain for a company that cost that company a customer.
As soon as the basic cause has been discovered, actions can be put in motion to make sure this can be either circumvented, in the case of a negative result, or repeated in the case of a positive one. If the basic cause of a problem isn’t correctly recognized, then only the symptoms will be dealt with, not the actual reason for the problem itself. Dealing with situations in this manner can result in higher costs, inferior quality, sluggish delivery or possibly all three.
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