LANGUAGE OF LEAN
Root Cause
The ultimate reason for an event or condition.
The Root Cause Analysis brings you to the ultimate reason for an event or condition
Methods used in the root cause analysis help you to identify the actual causes of defects or problems in your goods or processes. The whole idea behind a root cause analysis is to understand and get rid of the source of the problems and not to fight the symptoms. Thinking about quality management the Root Cause Analysis is a big part of it and has an impact on Six Sigma and 8D processes.
The root cause analysis is in demand when problems can no longer be solved with pure empirical knowledge (e.g. known products are used in new operating conditions and cause problems there).
The basic idea of all Root Cause Analysis methods is first of all to describe the problem (symptom) as precisely as possible, to limit the potential sources of the problem and then to systematically follow the error path. A distinction has to be made between purely theoretical analyses and experimental root cause analysis.
Known theoretical methods are the 5-Why question technique and the 6M method (Ishikawa). These methods, however, often suffer from the limitation to consider complex problems insufficiently. For example, it is impossible to identify combined root causes.
For complex problems, Vester's system analysis shows very good results in practice. Using the so-called intensity relationship matrix, expert knowledge is systematized and thus contributes to new approaches.
The area of root cause analysis also includes experimental designs that have the goal of eliminating a problem. A distinction must be made here between problems resulting from the production and assembly process and those resulting directly from the components or combinations of components. One of the well-known methods in this area is the component exchange methodology, which represents a methodically and statistically proven way of eliminating problems caused by components.
Apply Root Cause Analysis methods to your quality problem.
6M methodology (Ishikawa)
Vester` intensity relation matrix
Problem identification and identification through statistical product analysis in ongoing production through a practically established multi-stage problem-solving approach.
Root Cause Analysis
5 Why
The 5 Why methodology is a well known part of the root cause analysis. Key is to ask five times in the row – why?
The 5 Why methodology is a well known part of the root cause analysis. Key is to ask five times in the row – why? It is not the only way to determine the root cause(s) of problems. Just to mention that it usually comes together with an ISHIKAWA analysis. If you want to get deeper into problem solving including ISHIKAWA and 5Why we recommend you the article taking on the 7Steps approach.
The practice of asking why five times in a row whenever a problem occurs supports you on identifying root cause(s) and to determine effective counter measures that are developed through the process of 5Why. Then it is a simple part of PDCA to develop and implement effective measures.
To be able to steer a wide product portfolio, survive the competitive pressure and at the same time satisfying your customers with a high quality product at a reasonable price can be a tough game. Most of the time you don’t have enough time to run the complete product development cycle, do your validation and verification… The end of the story is that you start production because you need to deliver – which automatically leads to mistakes in running daily business. Therefore, the simple method of 5Why can be used to support, not only, your quality department to get faster to the bottom of problems.
The solution for a problem is not always easy, sometimes the root cause is hidden. Therefore the method is an important element of the root cause analysis. One tries to get to the root of the problem step by step with why questions, because one assumes that several causal connections interlock. The system is easy to explain, but there is a lot behind it. If you really take the time to ask the questions carefully and discuss them, the results are extremely profitable.
You should go through these steps of the 5-Why method. Describe your problem as detailed as possible. As more facts you have, you are faster on getting to the bottom of the problem.
What is the difficulty?
When did it first occur?
How often does it occur?
Is this failure randomly coming or reoccurring in a pattern?
Can you repeat the failure?
What is the effect of this failure?
and so on….
It is very important to get a fast idea of the situation on site. Take the Gemba Walk as great opportunity to talk to the people who are actually involved and to see it with your own eyes instead of guessing from your office.
Avoid making assumptions at this stage - you may draw the wrong conclusions.
Keep calm and try to understand the complete context first.
Understanding the context is where the 5-Why method comes in. Gradually ask why questions in order to get a feeling for the interrelationship of effects. This works for many areas of the company, in production, but also in your private life.
Example:
Problem: I miss all the fun part with my kids…
Why do I miss so much? - Because I’m not often at home.
Why am I not often at home? - Because of my position at work I have long working hours and business trips.
Why do I have long working hours and business trips? Because I can’t get my work done in 8 hours and bad in delegating work.
Why can I get my shit done in 8 hours and miss to delegate things? Because I’m sloppy in prioritizing and time management and don’t trust others.
Why can’t I prioritize my activities and don’t trust others? Because I don’t have the information needed to do so.
Reverse conclusion: If I’m not getting the necessary information in a certain amount of time in an acceptable quality I’m not able to steer my employees but also miss the time with my kids.
Sometimes 2 questions are necessary, sometimes 8 or even more to bring you to the “right” conclusion. But don’t give up half way.
Develop appropriate counter measures:
What contributes to solve the problem and who can implement which measures? How long will this take and what consequences will the implementation have?
First: I should try to have set timeframes with my kids which are holy and untouchable.
Second: I should define what information for me is necessary to run my company.
Third: According to the defined Information I train my employees what I need.
Fourth: I implement a clear systematic approach that I have all information latest at 11:00.
(DING DONG - Sounds familiar? BINGO — Shop Floor Management with a functioning meeting cascade.)
Keep the wheel spinning!
No matter what – before start implementing ad-hoc whatever you find best – take your time to identify what actions contribute to a real long term effect, what effects it will have on other areas, etc. Nothing worse than if you think you are doing something great but in reality you make it even worse.
The cycle of questions is often interrupted too early. The real cause is then not really eliminated and after some time there are repeated difficulties.
You can test it: If the reverse of your assumptions works, you are probably at the end of the causal chain.
As mentioned in the beginning another way is the ISHIKAWA diagram
Just keep in mind that not like with the ISHIKAWA the 5 Why only leads you to one cause for a problem. But as always in life there can be more than just one that leads to an effect. Therefore, the combination of 5Why and ISHIKAWA gives you the best approach to determine causes. It will allow you to represent several major and minor causes that can contribute to the solution.
Get the big picture with an ISHIKAWA drill it down with the 5Why.
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