How do you get Root Cause Analysis to work effectively? – Part 3: C & E Analysis

I discussed in part 2 of this series of Root Cause Analysis articles that 5-why analysis is a ‘deep and narrow’ approach to fixing immediate problems. In part 3 of this series of discussions I’d like to talk about a technique that’s better placed to resolve more complex issues, and especially where it’s necessary to explore multiple causes of failure, both real as well as potential.

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Here I’d like to discuss the Cause & Effect analysis technique.

A bit of background

In the 1960’s Kaoru Ishikawa, a pioneer of quality management systems, popularised the Ishikawa (or Fishbone) diagram. Ishikawa was instrumental in translating and further developing the ideas of Deming and Juran into the modern Japanese quality systems. He introduced the concept of ‘Quality Circles’ in 1962. Interestingly, his Quality Circles concept specifically targeted Gemba-cho (i.e. Leading hands or Supervisors) to be capable of driving their own quality improvement within their own workplace areas. Keep this in mind for the time being, and recall my key message in part 2 of these discussions – about the importance of the ‘people in the process’.

A Cause & Effect diagram intends to relate a single failure mode (defined in the head of the fish) with all possible causative factors. These causative factors being classified typically into six ‘affinities’.

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The ‘affinities’ were originally defined as the 6M’s (Man, Materials, Machines, Methods, Measurements and… Mother Nature). We’re a bit more refined in these classifications these days though, and an important message to convey here is that it doesn’t really matter what you call these affinities, so long as they’re meaningful to the type of processes you work with.

The original 6M’s originated from the manufacturing sector and they don’t always have a completely suitable relevance to some Service or Administrative processes (although ALL processes have procedures/methods, materials/equipment, and people). There don’t even have to be six affinities – less than or more than six is quite OK. All we’re trying to do is pigeonhole ‘types’ of possible causes. Take a closer look at the two diagrams above for example.

What distinguishes a good Cause & Effect from a bad one?

An important point to make about what’s defined in Cause & Effect diagrams is that, because it’s a tool to expose failure, everything should be stated in the negative (both failure mode and potential causes). Any other form of cause or effects statement doesn’t help the understanding – there needs to be a basic and easy to understand cause-effect relationship, otherwise this technique has very limited value. However, when properly prepared they aren’t just useful methods of information collection, they can also become very valuable training documents, and this is something often overlooked with the development of these diagrams. Make them easily and universally available to the process and you have something that supplements the operating procedures (how-to) with the reasons (why-so).

Just telling people what they have to do, you’ll just get a ‘ho-hum’ reaction, use Cause and Effect to teach them why things have to be done you’re more likely to get a ‘ah-ha’ reaction.

I asked at the outset of this discussion if you’d keep in mind the ‘people in the process’. This technique, just like 5-Why works best when it’s carried out as a ‘team’ approach – it’s vitally important to have representation from inside the process in these teams. They’ll be the ones who expose the real reasons for process failure and they need to be the ones who contribute to the problem solutions, otherwise effective process change just won’t happen.

There’s a big danger with this technique though. Yes, it’s designed to extract knowledge from process experience. But that means that’s all it might do – it could just capture what people already know HAS happened! It doesn’t easily push people to consider WHAT COULD happen. So this technique, if applied in this ‘rear view mirror’ mode will, at the vey best, only really match the ‘deep & narrow’ analysis that 5-Why achieves.

What’s needed is an additional ‘push’ to develop a ‘deep & WIDE’ analysis of process failure so that all other ‘potential’ forms of failure can be assessed. If these are considered a high enough risk, then they also can be included in process change to make the process even more robust from failure.

OK, so how on earth do you document potential causes if no-one has any experience of them? A conundrum!

How do we know what we don’t know?

Well, it can be done. All that’s needed is a logical mechanism to help people stay focussed on the process – and also a willingness to keep an open mind about ideas generation, which can sometimes come up with suggestions that we’d usually just cast aside as ridiculous.

A simple and effective approach to managing the problem of delving into the unknown is to have Input/Output maps of the process at hand. Specifically using the inputs (the drivers of the process at each step) that can act as ‘primers’ to ask the question ‘how does this process driver have any possible influence on our failure mode(s)’?

Here’s a story (a true one in fact!). A high-quality magazine printer had issues with the paper tearing when feeding into their printing presses. This was really bad news, it damaged the print equipment, created a lot of lost time, cost a lot in wasted paper, caused serious health & safety issues and really wound up their customers. Every time they had a paper tear problem, they investigated, and usually did a reasonable job of fixing them. Unfortunately they continued to get new paper tearing issues. All they were typically doing was ‘reacting’ iteratively as each ‘potential’ problem developed into to a ‘real’ problem. All ‘potential’ problems are ticking time bombs! They will bite you at some point in time if you don’t mitigate effectively against that possibility.

So our printers did some brainstorming using Cause and effect diagrams to collect their thoughts – it went something like this…

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When you condense this into less ‘fluffy speak they ended up with a list of what problems they remembered they (used to) have. Hmmm.

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By the way, these people were clever, they DID do something with this information, they drilled down into each using 5-Why, and they put relevant changes back into their process – which was good. But sometimes these changes were informally adopted though, so lessons learned were often lost and not passed on to new staff – which was not so good.

So they decided to look in a bit more detail. They identified at each process step what went in (influencers) and what came out (expectations). A simple map of the process…

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And then they took a bit of time to start asking questions about how each of the process inputs could influence their problem…

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And so they started populating their knowledge with stuff they didn’t even know they knew…

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The outcomes from their use of this in-depth and logically focussed approach were very rewarding:

  • They fixed processes in a way that significantly reduced the incidence of their problems
  • They ended up with highly populated diagrams that they used as in-process reminders and as quick training aids
  • They found that people in the process understood the causes and therefore stuck to new procedures being implemented
  • They found their customers were happier, not just with less impact of equipment downtime and poor quality print, but also they were filled with more confidence that these were the printers they felt most comfortable doing business with

In fact the extension of this new way of developing their process knowledge extended business wide. These are simplifications of their journey though – but their fully populated analysis became a benchmark for the rest of the organisation.

So, key messages: how do you get Cause & Effect to work effectively?

  • Cause & Effect analysis is a better technique to use when there may be numerous possible causes of failure. Although 5-Why is a good ‘deep & narrow’ technique for fixing immediate problems quickly, Cause & Effect is a better technique for ‘deep & wide’ investigations.
  • Use it when you want to explore all actual AND potential causes of failure in a system.
  • Brainstorming isn’t Cause & Effect but Cause & effect uses brainstorming techniques to extract knowledge from the process
  • Have a logical approach to establish ‘potential’ causes. Develop Process Input/Output data to drive this logical process
  • Use the output from Cause & Effect, don’t lock it away. They can become extremely useful documents for training as well as just general knowledge refreshers
  • Have a ‘team’ approach to root cause analysis and always involve the people in the process
  • You will NOT get long term solutions if you don’t get buy-in from the people in the process



And so finally, in part 4 of this series of articles I’m going to bring us back to our starting point and explain how all these analysis techniques are really just variations on a theme, and why you shouldn’t be afraid of tackling the more complex analysis tools (once you’ve got enough people able to deploy the basics effectively).


If you’ve not already seen Part 1 of this series of four articles ‘A bit of background’ by all means feel free to look it up on our blog page where you can also see Part 2: ‘5 – Why Analysis’


What sort of strategies do you use to make Cause & Effect analysis work for you, especially with regard to involving and getting true buy-in from the ‘people in the process’? Why not share your own ideas and experiences about getting the best from this technique.




2 thoughts on “How do you get Root Cause Analysis to work effectively? – Part 3: C & E Analysis

  1. Dear Bob, thanks so much for your insights—am sharing them with my graduate students.

  2. Dear Cheryl, I am pleased you have found these RCA articles of value. Anything that enriches your student’s knowledge that I can provide makes me feel that I am accomplishing my task of ‘handing on the baton’ of improvement tools to the next generation!!!

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