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	Gorur Sridhar Some are of the opinion that a problem can have more than 1 root cause, but I feel it negates the very definition of ROOT CAUSE i.e. Root of the causes which is only one. Once you solve it which is a major contribution factor then the second most contributor can become the root cause to be eliminated and so on.
	Vishwadeep Khatri Interesting question, Gorur. Working on one factor at a time has its advantages in some cases especially if causes are not independent of each other. I do not think I would limit myself to one root cause at a time in a team problem solving situation, especially when members have capability to work on few independent issues simultaneously. What do you think?
	Gorur Sridhar That is OK ..working in parallel, but what I mean is that, definition of root cause is that there is only 1 major cause to the problem. Once you address the next most significant cause becomes the 2nd root cause hope this is right.
	Vishwadeep Khatri Let us talk about delay in flight take off as an example . I may find baggage loading delay, delay in food supply and passenger security check delay as three reasons having same frequencies. It may not be easy for me to consider one of the three as a single root cause or major contributor. Considering all three as root causes should be fine. What do you think?
	Gorur Sridhar We have to try to give weightages for the factors either in terms of loss of revenue or quality or availability etc. so that we single out one of them and then proceed.
	Mohan P B Would agree with VK in that limiting oneself to a single root cause may be detrimental to solving the problem completely. The singular aspect of "Root Cause" is figurative and need not be taken literally. In most real problems there are many root causes, resolving which would solve the problem completely. Resolving only one root cause will improve the situation but not completely. For example, if the problem requires improving Quality from (say) 90% to (say) 99%, there could be four or five different root causes, resolving each of which may improve the Quality by 1% to 3%. But resolving all of them will help us reach the target of 99%
	Vishwadeep Khatri I agree Partho, it may be a system of interacting root causes in some cases ( where interactions exist ). The focus in such cases shall be on the system and not one specific cause).
	Gorur Sridhar That is ok, what I am trying to understand is that is it Root Cause or Root CauseS? We always ask to find out the root cause and finding out the root causes does not sound to be logical!
	Partho Banerjee LSSBB I agree gorur, the terms stands as "Root Cause" it is more of a symbolic term.  generally we reffer to as "Finding the Root cause" because, ultimately we put 90% of our efforts in diminishing the effects of that one main cause and rest for the interacting causes. The ratio would vary depending on situation & based on the conclusions from the data.
	Shamik Kumar It is one of the most common errors in problem solving that we make, with assumption that for any problem there will be only 1 cause which can be called as root cause, its important for team investigating the problem to keep an open mind and analyse each probable cause and their effect thoroughly.  Root cause can be one specific leading to your problem or it may be because of interaction of multiple causes, in second case it will be difficult to identify one problem item, instead the team should work systematically to validate and correct all identified causes, also in second case some time people do call it as system failure/ failure of risk assessment or etc so to just arrive at one problem but then it becomes a generic cause and most of the time they end up missing on some or the other smaller problems which in future becomes big.
	Mayank Gupta Gorur - a problem can definitely have more than 1 root cause (or "Root Causes"). I'm surprised to know that there are people who think that there has to be only 1 root cause. How many of such causes you deal with at the same time depends on the appetite of the business and the project team.
	Christopher Sequeira (LION 2900+) It is good to find out the root causes and their interconnections. Figure out which of them is the highest contributor and attack it before the others.
	Doug Ford Problems can absolutely have more than one root cause and usually do. The trick is to understand the tree of the problem to see the various cause and effect branches and understand the relationship/dependencies. Once you can understand that, you can figure out the most effective way(s) to break the cycle to eliminate the problem from resurfacing.
	Ashok Motwani Gorur  In your question you are suggesting that perato thinking is utilized where the biggest bar (which contribute most to the problem) is tackled first. Correct me if you think I am off-base. However others responses are also correct where independently no one cause could improve the situation at hand but interactions can be the prime objective to handle so problem can be solved. Picture how "Root" looks like. The answer is - it depends.  From the trunk of a tree or plant many shoots or one shoot starts and then divides into many branches. Similarly it is dependent on the type of problems being solved (maybe.....) and the perspective of an individual/team who is leading the problem solving event. Question or comments are welcomed. Ashok
	John Predmore I think a problem can have more than one root, same as a plant can have more than one root branch. I do think some people mislabel every factor in the causal sequence a root cause and that is a disservice. My definition of root cause is 1) something that is not supposed to happen and 2) something we can control or prevent. By this definition, if I slip on an icy walkway, the root cause is not the ice. If it is raining and the temperature is below freezing, ice will form. I cannot prevent the rain or the cold temperature. In this circumstance, I need to probe deeper using Five Whys, for example. Why did I fall? Maybe I did not know the temperature. I can hang a thermometer by the door. Maybe I did not see the ice. Improving lighting could help. Maybe my shoes have poor traction. Better shoes could help. Any one of these could be considered a root cause as long as fixing one of them is sufficient to prevent recurrence.
	Ashok Motwani John  Good example and explanation. Thanks
	Christopher Ayres A root cause it the deepest cost of a concern, kind of like shedding the other concerns to get to the root. So the answer is one.
	Christopher Ayres Miss understood the question.
	Christopher Ayres At the same time there is only one critical x. Take it easy on me I just got verified green belt.
	Sharon Vollers Well Root cause theory generally teaches that there is only one root cause to a situation and generally I support that position and believe we should push for that. Having said that however, Absolutes tend to be problematic in that they represent our current theory/ knowledge and close us off to the possibility of other discovery. This would bear some scientific analysis.
	Raju MRC "Problem" is the overall high level dissatisfaction/ non-compliance that is observed in a system. Every problem with have one or more "Failure" associated which together lead to the problem. Each "Failure" in turn will have one or more "Defect" associated due to which the failure occurred.  Root cause is always associated with the "Defect" - We do the analysis at this level to know, what led to defect getting introduced?. This question always leads us to many causes, but only one "Root Cause".  So, when we look for root causes from a problem perspective, there will be many.
	Martin Steimle Hi,  during root cause analysis you want to identify "the" root cause and eliminate it.  Some people use the word "true" root cause. One of Toyota's principles is to identify the root cause to ask the 5 Why's which seems an efficient way to come close to "the" RC. During this journey of asking the 5 Why's you might face several branches and you have to decide within the xfct team which branch to explore next and then do experiments to justify the identified RC. hope this helps a bit, Martin
	Pascal Chaloyard If you are considering one problem usually you have combination of a risk factor and a triggering element
	Steve Borris Consultant and Author There can be more than one cause for an issue. The point about the Pareto made above suits the situation well. I do get a bit worried by the belief by some problem solvers that the right solution is found every time. This is simply untrue. I would very rarely recommend implementing multiple "solutions" at once. I have seen situations where multiple improvements were made simultaneously and, as well as the problem not being fixed, new problems were created. But I guess it depends on the complexity of the solutions. Just because an orchestra has a lot of instruments does not mean that they should all be playing different tunes at the same time. Identify the possible causes. Identify the solutions. Define monitoring tests to ensure resolution. Prioritize for implementation and plan a schedule. Only if we can guarantee that implementing a second solution will not have any negative consequences or if the problem area is very hard to access, would I consider multiple fixes --- and I would need to be sure all the folk involved were fully aware of the risks. Steve
	Sanjay Rawat (1500+) As per my opinion 5 why analysis is for finding the ultimate root cause of the problem.. There are possibilities that we might find minor causes around the main cause which we can ignore and continue to identify the main root cause.
	Martin Leighfield Prof Dip Mgmt (Open) Using the example above, is the level of dissatisfaction the problem or is it the effect of the problem? People leaving could be the effect of bad customer service so are we looking at improving the level of dissatisfaction or are we focusing on the bad customer service. And focusing on one cause may not be the true answer as the output of a process is the sum of ALL it's inputs.
	Ashok Motwani Steve, well said about how to implement countermeasure.  No cause should be considered insignificant and each countermeasure implemented could create another symptom. Martin, you are right about understanding first which problem is being solved so first step is to clearly and succinctly definition of Problem in measurable units must be completed which will provide the scope and time frame. Once a countermeasure achieves the quality levels/ goals required or expected by the customer (internal or external) there comes a point in time when additional analysis and finding causes becomes unhealthy financially and becomes a drag on resource availability. Comments are appreciated. Ashok
	Partho Banerjee LSSBB I would like to add to Ashok and steve..for the same reason we identity our secondary parameter/s which shouD not be affected while we are workng On the root cause/s. So active targEting of primary parameters and monitoring of secondary parametERs
	Alan Charles Some great thoughts, hope I can add by coming at it differently  Consider every problem with a make ( why it happened) and a flow ( why it got out) you will 2 root causes from these. Based on whatever you call it, FMEA, QA Network ( Toyota speak) and several versions/themes around it, you can have a strong c/m to RC1 and no need to have a RC2 c/m pending a matrix evaluation. A bit off topic that bit, but its a way to show you can have multiple RC's. They are all important bits, but the top of the funnel, to clarify the problem and then cause and effect an have a massive bearing on the 5Y you go down. Depending on anyone's level in a company you can ask another Y, RC's on systems are the key. Ignoring all this, and may seem strange, but what did the people get out of the investigation, this shows training, culture and development more than the RC to some extent. Its the ownership of this element by the responsible section which is often lacking leading to RC problems.
	Femi Obiomah While initial theories have stated that there should be one root cause, I believe like in other cases, modifications can be made drawing from experiences and applications. We now have the fault tree as well. very few trees have one root. Take customer dissatisfaction for example, its easy to attribute poor business plan as the root cause. There are cases however in which even when there is a proper business plan you still have customer dissatisfaction, There is the need to address all the possible causes.
	Steve Hall As a minimum, each experienced issue has 3 root causes.  Occur - why it happened in this case Escape - why it passed the process and on to the next customer Systemic - what element of failure avoidance failed to predict and manage the issue There can, of course, be multiple root causes of the occur. Sometimes complex issues actually interact, and the whole issue might not be an issue, unless all the root causes happen.  We don't have to hang on to the concept of having a single "root cause" if it does not fit our situation. There could be a pareto of issues and a significance of contribution - as can be found during a Design of Experiments event (for example).  Escape is usually simpler, in that the issue was not being either looked for or detected - which brings us to the Systemic root cause.  Was the issue, or its significance, predicted / predicted correctly in the failure mode avoidance activity? This can be done during D7, but it helps to start the thinking off, when working through the Root cause analysis.  You could argue that this systemic root cause, is the truest root cause of all - which I think it is. So, in conclusion, there could be many root causes, that all happen at once, or individually.  Verification and Validation will go a long way to prove that you have made a positive impact on the issue. But, it might not pick up everything in the first round of the issue, but you might reduce it to acceptable levels - however that acceptable level is defined.
	Steve Hall BTW - complex issues with potentially multiple root causes, is where the world of 6-Sigma takes us beyond the discrete, time line/event orientated world of 8D
	Ashok Motwani Thanks Steve for bringing up the 3 points of failure in a out of standard condition which is called "defect" for which root cause analysis has to be done. Typically an individual or a team focus on one of the failure mode and are unable to eliminate and prevent the recurrence. Great response to the original question!
	Mark Reinard Sarsonas I'd say that'd depend on the scope and limitation of the charter. The more specific it is, the greater the chance we can point to a single root cause. I haven't done a project to support this idea though.
	Christopher Vallee As a TapRooT Root Cause Instructor, we started our process on the concept that multiple roots can cause individual problems. These individual problems (actions or actions) either initiated the incident (the worst consequence), failed to catch it in time to mitigate or made it worse. Each one of these problems having their own root causes. Think about a fire or explosion. It takes at least 3 main ingredients to come together in the right sequence to create it. We can argue all day like the number of disagreements in the posts above and been no closer to preventing the incident from occurring than we are now on deciding on one for multiple root causes. There is not one root cause for anything. There are instead multiple issues that if we reduce or eliminate will reduce the probability of an incident occurring again. Worst case scenario, lets say we voted on the fuel source only for the fire and then fix it this time. By ignoring the other factors, the uncontrolled ignition is just waiting for it's next fuel source.

Vishwadeep Khatri
Let us talk about delay in flight take off as an example . I may find baggage loading delay, delay in food supply and passenger security check delay as three reasons having same frequencies. It may not be easy for me to consider one of the three as a single root cause or major contributor. Considering all three as root causes should be fine. What do you think?

 

My Reply -- One cannot stop thinking at this level. Cause & effect. What is causing delay in baggage loading, food supply or security check? Is there any causal connection which connect all the three?

Remember, any connected system does not work in isolation.. There must be a connection.

What if due to some crisis airport is shortly staffed (just an example). This is causing all such delays which are more human resource dependent.

Solving this would solve all above