Root Cause Analysis tools (RCA tools) are investigative techniques that assist in pinpointing the cause of a problem. They help managers and operators focus on the problem at hand without getting side-tracked. The proper application of RCA tools makes it easier to locate and fix the true root cause of a problem in your factory, thereby minimizing downtime and increasing output.
Let’s examine four of the best Root Cause Analysis tools, the way to use them and their benefits for problem solving.
1. Pareto Chart
The Pareto chart is a great tool to kick-start any Root Cause Analysis. Pareto charts bundle up information and present it in the form of a comprehensible graph. Through the combination of a histogram and a line graph, the Pareto chart gives a great overview of the problems that exist in an area and the frequency in which they occur. The histogram’s bars are arranged in order of significance, making it easy for managers to see which problems cause the most downtime.
Looking at the above image, it is clear that the problem represented by the changeover bar is the cause of a significant amount of downtime. This observation could lead in an investigation into the source of the problem, which, by using other RCA tools, will become gradually more defined.
Although Pareto charts are easy to make and can be used in any kind of industry, they must be fed with good data to be complete and effective. If you don’t have quality data, it is better to leave the Pareto chart aside, and instead use gut-feeling and instinct for this step of your RCA.
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2. 5W1H and it’s variants
The 5W1H method is a great second step in your Root Cause Analysis. By asking six questions, this RCA tool guarantees that everyone on your team understands the aspects of a problem. This technique consecutively asks what the problem is, when and where it occurred, who was involved and why and how it happened. It thereby divides the problem discovered by way of the Pareto chart into factual components. The exact (amount of) questions may vary. Some companies, for example, add how much to the questions to figure out how much loss a problem is causing, creating 5W2H.
Answering all six questions will clarify what the problem is and on what should you focus as the further steps of your RCA. While the Pareto chart defines priorities, 5W1H characterize it. The 5W1H method does not cost any money, only takes a short amount of time to perform and can bring a welcome clarity before diving into the issue. It can easily be done on a whiteboard or even on a piece of paper.
3. Fishbone diagram
The fishbone diagram (also called the Ishakawa diagram or cause-and-effect diagram) is a step-up from the 5W1H method. It makes it possible for everyone involved in an RCA to share their ideas about the cause of a problem. These ideas are grouped into a diagram that roughly resembles a fish skeleton.
The branches of the diagram are formed by different causal categories (in manufacturing, these generally consist of the 5 Ms), while the central horizontal line points to the problem. This RCA tool is great for getting a diverse set of people involved in a brainstorming session: Everyone is free to pitch their ideas, and the form of the diagram guarantees that a large amount of ideas can be arranged in a coherent way.
After all possible causes are entered into the diagram, they can then be empirically examined. Everything that isn’t causing the problem is crossed off the diagram, leaving a set of causes that cannot be ruled out.
4. 5x Why
The 5xWhy method further inspects the possible causes left over from the fishbone diagram. By continually asking why something happened, a tree of cause-and-effect is formed, making it possible to reach the root cause in a structured way. The question why does not necessarily have to be asked five times; it must be asked as many times as is necessary to get to the root cause.
As you can see in the example above, this RCA tool can be used to reach the cause of problems ranging from mundane mishaps to complex factory issues. This method is great because using instinct at this step of an RCA might lead into wild goose chases. Instead, a clear and logical chain of causes is formed, and each cause can be confirmed or discarded. Moreover, to ensure the logical integrity of this technique, the tree can be ran through in the opposite direction.
4Industry’s Root Cause Analysis Tool
The 4Industry platform encompasses a virtual version of the 5xWhy method. This has lots of benefits, because instead of having to deal with physical mediums like paper for carrying your 5xWhy tree, information is stored digitally. This means that if the problem re-occurs in the future, your archived RCA tree can be easily accessed.
Furthermore, individual steps in the 5xWhy method can be assigned to personnel at a distance, who will be able to understand their task, as they can see the analysis themselves. Last but not least, 4Industry allow people from other plants in different countries to connect to the 5xWhy board and participate in an analysis or view the result.