Pros and Cons of Different RCA Methods with Shon Isenhour
Shon has been on our past episodes. He is the founder of Eruditio LLC, a co-author of several books, a conference presenter, and he has been in maintenance and reliability for quite a while. He has been in the reliability sector for 20 years.
This episode focuses on:
- What is root cause analysis
- What are the Different Tools of RCA
- How do You Pick a Tool to Use
So, what is root cause analysis?
Root cause analysis is a problem-solving strategy. It involves dissecting a problem thoroughly and understanding how to address not just the surface issue but every aspect. We look at what is to be eliminated or reduced to ensure that the problem does not occur again. You reduce the risk to a level that you can manage and afford.
What are the Different Tools of RCA?
There are a lot of tools and these are just some of them
- Pre-analysis tools
- Time tools
- Tree tools
- Transparency tools- for big problems like performance gaps
The Tree Tools
Why should we use them?
Where should we use them and what are the shortfalls?
Tree tools are the most common tools available.
One of the Tree tools is 5Ys
5Ys- ask why 5 times how something contributes to an issue. Adding ‘ANDs’ and ‘ORs’ to all branches to have the ability to see where things come together and what could be the problem factor. This is great in a root cause investigation where evidence was destroyed or lost.
The tree tools best fit where you have one specific problem. Fault trees are also used with other tools such as the time tools.
Where do tree tools fall short? Can they be used for short or complex problems?
If the problem is very large or has very broad amounts of forcing functions coming in, the tree is too broad even for the surface you are working on. It will become inefficient. Being visual is a pro but the amount of intensity might be problematic. You will overrun the sides of your whiteboard.
Tree tools don’t allow you to see risks and potential probability in the grand scheme of things. So, if you are mapping out potential causes, there are some that are very likely to have occurred while others are very unlikely to have occurred, so you do not have a good way of evaluating the risk associated. That means switching over to transparency tools.
This is a set of three tools but the most popular is the fishbone.
Fishbones. A way of understanding contributing factors and causes. They only deliver higher-level causes in most cases.
Time tools are often neglected but are the most powerful tools in problem-solving. The tools are then narrowed down to two steps:
- Sequence of events
- Expansion of the sequence of the events. It branches into an event and causal factor and is a bit complex. You use the branching mechanism to understand problems when you cannot put things in sequence.
The limitations? You may need extra tools such as a fault tree. In this situation, it is not a tool enough for the job. It is great for understanding what happened in the past and what will happen in the future.
What other tools are used in the field?
The ones we have mentioned are already common but there is the barrier analysis where we look at all the different systems that could stop something from occurring.
Most of the other tools are a take on one of the tools like change analysis. Change analysis is the idea where you check what is different today from what was working perfectly. You look at what changed when it changed and how did it change. This is seen in a root cause methodology.
How do You Pick a Tool to Use?
We have to be comfortable with transitioning as a situation changes. This is because as a situation changes, the tool might change. So, in most cases, the best fit is the tree tool. But if there are a lot of changes that call for flexibility then transition tools will do. If you have no idea of what happened then time tools will be suitable.
Transparency tools are for big problems.
Tree tools are for specific failures
Time tools help us get an understanding of all the contributing factors where there is a lot of missing data.
What is needed?
Stick to the basis of root cause analysis and do them well. There is a huge ROI. Don’t be scared of root causes, start small and have a process that informs you of what you should and should not do. Make sure you communicate your RCAs. A 50-page document will never be read as much as you need the data, package it right even in one page.
Just go and do some RCAs. You will take longer but it will get better. There is no silver bullet but as you put other things in play, more value will be added.
- HP Reliability
- James Kovacevic’s LinkedIn
- Reliability Report
- Eruditio Supports: www.help.eruditio.com
Shon Isenhour Links:
- Shon Isenhour LinkedIn
- Shon Isenhour Twitter
- Eruditio Linkedin
- Nasa Fault Tree Handbook
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