Root cause
Encyclopedia
A root cause is rarely an initiating cause of a causal chain
which leads to an outcome or effect of interest. Commonly, root cause is misused to describe the depth in the causal chain
where an intervention could reasonably be implemented to change performance and prevent an undesirable outcome.
In plain English a "root cause" is a "cause" (harmful factor) that is "root" (deep, basic, fundamental, underlying or the like).
The term root cause has been used in professional journals as early as 1905, but the lack of a widely accepted definition after all this time indicates that there are significantly different interpretations of exactly what constitutes a root cause.
Many governmental investigation agencies avoid the term or use it informally. Others use it in a stilted formalistic or bureaucratic manner. The National Transportation Safety Board, with an excellent investigative reputation, uses the term "probable cause." (In law enforcement "probable cause" has a very different meaning.)
A common view of "root cause" follows.
Every adverse effect is the result of a set of direct factors, the absence of any one of which would have resulted in the effect having been different than it was.
Each of these direct factors was the result of deeper direct factors.
If the probing goes deep enough one finds harmful factors that deserve the designation "root cause."
Once an investigation gets to one or more root causes it is good practice to check the work with the following queries:
The two biggest differences in viewpoint regard the possibility of an outcome having more than one root cause.
This viewpoint results in the identification of a single root cause that provides a clear direction for preventing an undesired outcome. The subjective criteria used for selection of the root cause from among the contributing factors has been criticized as being arbitrary and inconsistent.
One basis for the argument supporting this as the ‘proper’ interpretation is the decomposition of the words in the phrase – the root cause is the cause at the root of the outcome. While there may be nuances in the meanings of the words, the common usage of the words lead to a straightforward and simple interpretation.
However, the notion of a single root cause is the exception, not the rule.
Every harmful effect that has ever happened occurred after the stage had been set for it to happen. The factors that set the stage for the effect are sometimes called "set-up" factors or "vulnerability" factors.
But many harmful effects for which the stage had been set do not happen. Thus there must have been a triggering factor that converted the latency to an actuality. Triggering factors are also called "initiating" factors or "precipitating" factors.
There could be "root causes" associated with each set-up factor and each initiating factor.
Most, if not all, harmful effects could have been milder or less serious than they were. Thus there must have been exacerbating factors that made the effect as bad as it was over and above the minimal set-up factors. There could be root causes associated with each exacerbating factor.
The result of this philosophy is a branching model that attempts to incorporate all the identified ways that the outcome could be prevented. The inclusive model provides a variety of corrective actions that can potentially break the causal chain.
One basis for the argument supporting this as the ‘proper’ interpretation is the common illustration of the model with the undesired outcome at the top and the causes spreading below like roots spreading from the trunk of a tree.
is knowing when you have found a bona fide root cause. A checklist of the characteristics of a root cause can help the analyst separate pseudo root causes from real ones.
A 2010 paper on Change Resistance as the Crux of the Environmental Sustainability Problem used root cause analysis to find two main root causes of the sustainability
problem. The paper presented three characteristics of a root cause:
While the paper dealt with a social problem, the three characteristics apply to problems of any kind.
). The direct causes often result from another set of causes, which could be called intermediate causes, and these may be the result of still other causes. When a chain of cause and effect
is followed from a known end-state, back to an origin or starting point, root causes are found. The process used to find root causes is called root cause analysis
.
The usual purpose of attempting to find root causes is to solve a problem
that has actually occurred, or to prevent a less serious problem from escalating to an unacceptable level (see Near miss (safety)
, for example). The basic concept is that solving a problem by addressing root causes is ultimately more effective than merely addressing symptoms or direct causes. Consider the following example, where root cause
leads to effect 
, with a few intervening steps.
Assume each of these factors is as described below:
The effect,
, could be prevented by addressing any of the other factors. For example, attaching jumper cables from another car (addressing factor 
) will probably allow the problem-car to be started. However, this solution is not likely to provide long-lasting relief from the undesired effect, as factor 
will ensure that the car shuts down again in a very short period of time. Addressing factor 
by repairing the alternator may solve the problem for a longer period, but factor 
will eventually result in another age-related breakdown in the alternator. The alternator could be replaced with a new unit, addressing factor 
, thus allowing the car to be driven for an extended period of time. However, factor 
will eventually ensure that the car breaks down again for some other reason. Clearly, a better solution to the problem (and many other potential problems) is to maintain the car properly, which addresses factor 
, the root cause.
Note that the preceding example highlights one difficulty with root cause analysis: knowing when to stop. That example could have been carried further to ask why the car wasn't being maintained, and then why the vehicle was designed such that this maintenance was even required. It is often the analysis' frame of reference that determines where the stopping point ought to be. For instance, if the example is viewed from an individual vehicle owner's frame of reference, then factor
may represent a valid stopping point. However, if the frame of reference is moved to the vehicle manufacturer, dealing perhaps with hundreds of thousands of such problems, the proper stopping point may indeed lie in the realm of design.
Thus, the root cause is a function of who owns the problem and what corrective action they choose to prevent recurrence. This perspective holds that any root cause is relative and can not be determined until the owner attaches a solution to it. The solution must prevent recurrence, meet the owners goals and objectives, and be within the owner's control to implement.
An issue closely related to solving an existing problem is to foster learning that will embed knowledge (within a person, group, or organization) that may help prevent similar problems from occurring in the future. Such knowledge is often referred to as lessons-learned. Gaining such knowledge, retaining it, and using it effectively is one of the goals of a learning organization
engaged in continuous improvement.
Although checklists like the one in the section above on Characteristics of a root cause are beginning to help, widespread disagreement remains in the types of conditions that can reasonably be considered root causes. One view holds that, in theory, one would have to return to the Big Bang
or point of Creation
to find true root causes. An alternate viewpoint is that one need only consider factors within the boundary of the system
that exhibits the problem. The former is usually used as one argument against attempts to single out specific factors as root causes, while the latter (or some version of it) is usually proposed as a practical bound within which useful information can be obtained.
Practitioners of root cause analysis often define what the phrase "root cause" means for a particular setting and application. The benefits of finding deeper layers of root cause tend to diminish after a certain point. The practical application of root cause analysis therefore often searches only as long as the benefit of answers outweighs the effort of the search.
, the idea of a line of cause and effect is disputed, in favour of the concept of causal loops. To quote Senge:
In addition, in an article in Quality Progress by Mark Paradies (Under Scrutiny) explains the psychological and philosophical limitations of cause and effect, especially as it applies to 5-Whys. The biggest drawbacks mentioned are 1) that cause and effect does not help investigators go beyond their current knowledge, 2) that cause and effect leads to the problem of "confirmation bias," and 3) that the use of cause and effect tends to lead to "single cause" answers in an increasingly complex world.
Some highly respected government investigation agencies do not routinely use the term "root cause", for example, the National Transportation Safety Board. See http://www.ntsb.gov/investigations/process.html
Causal chain
In philosophy, a causal chain is an ordered sequence of events in which any one event in the chain causes the next. Some philosophers believe causation relates facts, not events, in which case the meaning is adjusted accordingly.-See also:*Causality*Event...
which leads to an outcome or effect of interest. Commonly, root cause is misused to describe the depth in the causal chain
Causal chain
In philosophy, a causal chain is an ordered sequence of events in which any one event in the chain causes the next. Some philosophers believe causation relates facts, not events, in which case the meaning is adjusted accordingly.-See also:*Causality*Event...
where an intervention could reasonably be implemented to change performance and prevent an undesirable outcome.
In plain English a "root cause" is a "cause" (harmful factor) that is "root" (deep, basic, fundamental, underlying or the like).
The term root cause has been used in professional journals as early as 1905, but the lack of a widely accepted definition after all this time indicates that there are significantly different interpretations of exactly what constitutes a root cause.
Many governmental investigation agencies avoid the term or use it informally. Others use it in a stilted formalistic or bureaucratic manner. The National Transportation Safety Board, with an excellent investigative reputation, uses the term "probable cause." (In law enforcement "probable cause" has a very different meaning.)
A common view of "root cause" follows.
Every adverse effect is the result of a set of direct factors, the absence of any one of which would have resulted in the effect having been different than it was.
Each of these direct factors was the result of deeper direct factors.
If the probing goes deep enough one finds harmful factors that deserve the designation "root cause."
Once an investigation gets to one or more root causes it is good practice to check the work with the following queries:
- What are the other harmful factors that have equal or better claim to be called "root causes?"
- For each of those "root causes" what are the factors that directly resulted in the "root cause" as described? Is it still a "root cause?"
The two biggest differences in viewpoint regard the possibility of an outcome having more than one root cause.
Single cause
The single cause philosophy is based on the belief that there is a single cause for any outcome that, if prevented, would prevent the outcome itself. In this context, the root cause is the cause which dominates over all other contributing factors.This viewpoint results in the identification of a single root cause that provides a clear direction for preventing an undesired outcome. The subjective criteria used for selection of the root cause from among the contributing factors has been criticized as being arbitrary and inconsistent.
One basis for the argument supporting this as the ‘proper’ interpretation is the decomposition of the words in the phrase – the root cause is the cause at the root of the outcome. While there may be nuances in the meanings of the words, the common usage of the words lead to a straightforward and simple interpretation.
However, the notion of a single root cause is the exception, not the rule.
Every harmful effect that has ever happened occurred after the stage had been set for it to happen. The factors that set the stage for the effect are sometimes called "set-up" factors or "vulnerability" factors.
But many harmful effects for which the stage had been set do not happen. Thus there must have been a triggering factor that converted the latency to an actuality. Triggering factors are also called "initiating" factors or "precipitating" factors.
There could be "root causes" associated with each set-up factor and each initiating factor.
Most, if not all, harmful effects could have been milder or less serious than they were. Thus there must have been exacerbating factors that made the effect as bad as it was over and above the minimal set-up factors. There could be root causes associated with each exacerbating factor.
Multiple causes
The multiple cause philosophy stems from the belief that a root cause can exist for each of the contributing factors that were necessary for a resulting outcome. By preventing any of those necessary causes, the undesired outcome can be prevented.The result of this philosophy is a branching model that attempts to incorporate all the identified ways that the outcome could be prevented. The inclusive model provides a variety of corrective actions that can potentially break the causal chain.
One basis for the argument supporting this as the ‘proper’ interpretation is the common illustration of the model with the undesired outcome at the top and the causes spreading below like roots spreading from the trunk of a tree.
Characteristics of a root cause
One of the difficulties encountered in root cause analysisRoot cause analysis
Root cause analysis is a class of problem solving methods aimed at identifying the root causes of problems or events.Root Cause Analysis is any structured approach to identifying the factors that resulted in the nature, the magnitude, the location, and the timing of the harmful outcomes of one...
is knowing when you have found a bona fide root cause. A checklist of the characteristics of a root cause can help the analyst separate pseudo root causes from real ones.
A 2010 paper on Change Resistance as the Crux of the Environmental Sustainability Problem used root cause analysis to find two main root causes of the sustainability
Sustainability
Sustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of well being, which has environmental, economic, and social dimensions, and encompasses the concept of union, an interdependent relationship and mutual responsible position with all living and non...
problem. The paper presented three characteristics of a root cause:
- "A root cause is a portion of a system’s structure that 'best' helps to explain why the system’s behavior produces a problem’s symptoms. Difficult problems usually have multiple root causes. These are found by asking a succession of 'Why is this happening?' Kaizen-like questions until the root causes are found.
- "How do you know when to stop? A root cause has three identifying characteristics (compare to Rooney and Heuvel, 2004, who list 4 characteristics):
- "1. It is clearly a (or the) major cause of the symptoms.
- "2. It has no worthwhile deeper cause. This allows you to stop asking why at some appropriate point in root cause analysis. Otherwise you may find your-self digging to the other side of the planet.
- "3. It can be resolved. Sometimes it’s useful to emphasize unchangeable root causes in your model for greater understanding and to avoid trying to resolve them without realizing it. These have only the first two characteristics.
- "This definition allows numerous unproductive or pseudo root causes to be quickly eliminated.
- "The important thing is to not stop at intermediate causes. These are plausible and easily found. Working on resolving what are in fact intermediate causes looks productive and feels productive. Intermediate cause solutions, more accurately called symptomatic solutions, may even work for awhile. But until the true root causes are resolved, powerful social agents will invariably find a way to delay, circumvent, block, weaken, or even rollback these solutions, because intermediate causes are symptoms of deeper causes. One must strike at the root."
While the paper dealt with a social problem, the three characteristics apply to problems of any kind.
Some conditions, behaviors, actions, and inactions are never a root cause
When something is clearly the result of deeper more important underlying factors, practitioners are reluctant to accept them as "root causes." These include:- Failure to follow a certain provision of a certain procedure
- A specific instance of inadequate training
- The failure to identify a specific hazard
- The failure to adhere to a specific requirement
- The absence of a specific requirement
Application
Effects have causes. The causes may be natural or man-made, active or passive, initiating or permitting, obvious or hidden. Those causes that lead immediately to the effect are often called direct or proximate causes (see proximate causationProximate causation
In philosophy a proximate cause is an event which is closest to, or immediately responsible for causing, some observed result. This exists in contrast to a higher-level ultimate cause which is usually thought of as the "real" reason something occurred.* Example: Why did the ship sink?** Proximate...
). The direct causes often result from another set of causes, which could be called intermediate causes, and these may be the result of still other causes. When a chain of cause and effect
Causality
Causality is the relationship between an event and a second event , where the second event is understood as a consequence of the first....
is followed from a known end-state, back to an origin or starting point, root causes are found. The process used to find root causes is called root cause analysis
Root cause analysis
Root cause analysis is a class of problem solving methods aimed at identifying the root causes of problems or events.Root Cause Analysis is any structured approach to identifying the factors that resulted in the nature, the magnitude, the location, and the timing of the harmful outcomes of one...
.
The usual purpose of attempting to find root causes is to solve a problem
Problem
A problem is an obstacle, impediment, difficulty or challenge, or any situation that invites resolution; the resolution of which is recognized as a solution or contribution toward a known purpose or goal...
that has actually occurred, or to prevent a less serious problem from escalating to an unacceptable level (see Near miss (safety)
Near miss (safety)
See Close Call, for the 2002 film.A near miss is an unplanned event that did not result in injury, illness, or damage – but had the potential to do so. Only a fortunate break in the chain of events prevented an injury, fatality or damage; in other words, a miss that was nonetheless very near...
, for example). The basic concept is that solving a problem by addressing root causes is ultimately more effective than merely addressing symptoms or direct causes. Consider the following example, where root cause
leads to effect , with a few intervening steps.Assume each of these factors is as described below:
-
: car will not start -
: battery is dead -
: alternator does not function -
: alternator is well beyond its designed service life -
: car is not being maintained
The effect,
, could be prevented by addressing any of the other factors. For example, attaching jumper cables from another car (addressing factor ) will probably allow the problem-car to be started. However, this solution is not likely to provide long-lasting relief from the undesired effect, as factor will ensure that the car shuts down again in a very short period of time. Addressing factor by repairing the alternator may solve the problem for a longer period, but factor will eventually result in another age-related breakdown in the alternator. The alternator could be replaced with a new unit, addressing factor , thus allowing the car to be driven for an extended period of time. However, factor will eventually ensure that the car breaks down again for some other reason. Clearly, a better solution to the problem (and many other potential problems) is to maintain the car properly, which addresses factor , the root cause.Note that the preceding example highlights one difficulty with root cause analysis: knowing when to stop. That example could have been carried further to ask why the car wasn't being maintained, and then why the vehicle was designed such that this maintenance was even required. It is often the analysis' frame of reference that determines where the stopping point ought to be. For instance, if the example is viewed from an individual vehicle owner's frame of reference, then factor
may represent a valid stopping point. However, if the frame of reference is moved to the vehicle manufacturer, dealing perhaps with hundreds of thousands of such problems, the proper stopping point may indeed lie in the realm of design.Thus, the root cause is a function of who owns the problem and what corrective action they choose to prevent recurrence. This perspective holds that any root cause is relative and can not be determined until the owner attaches a solution to it. The solution must prevent recurrence, meet the owners goals and objectives, and be within the owner's control to implement.
An issue closely related to solving an existing problem is to foster learning that will embed knowledge (within a person, group, or organization) that may help prevent similar problems from occurring in the future. Such knowledge is often referred to as lessons-learned. Gaining such knowledge, retaining it, and using it effectively is one of the goals of a learning organization
Learning organization
A learning organization is the term given to a company that facilitates the learning of its members and continuously transforms itself. Learning organizations develop as a result of the pressures facing modern organizations and enables them to remain competitive in the business environment...
engaged in continuous improvement.
Although checklists like the one in the section above on Characteristics of a root cause are beginning to help, widespread disagreement remains in the types of conditions that can reasonably be considered root causes. One view holds that, in theory, one would have to return to the Big Bang
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
or point of Creation
Creationism
Creationism is the religious beliefthat humanity, life, the Earth, and the universe are the creation of a supernatural being, most often referring to the Abrahamic god. As science developed from the 18th century onwards, various views developed which aimed to reconcile science with the Genesis...
to find true root causes. An alternate viewpoint is that one need only consider factors within the boundary of the system
System
System is a set of interacting or interdependent components forming an integrated whole....
that exhibits the problem. The former is usually used as one argument against attempts to single out specific factors as root causes, while the latter (or some version of it) is usually proposed as a practical bound within which useful information can be obtained.
Practitioners of root cause analysis often define what the phrase "root cause" means for a particular setting and application. The benefits of finding deeper layers of root cause tend to diminish after a certain point. The practical application of root cause analysis therefore often searches only as long as the benefit of answers outweighs the effort of the search.
Criticism
In the arena of systems thinkingSystems thinking
Systems thinking is the process of understanding how things influence one another within a whole. In nature, systems thinking examples include ecosystems in which various elements such as air, water, movement, plants, and animals work together to survive or perish...
, the idea of a line of cause and effect is disputed, in favour of the concept of causal loops. To quote Senge:
- In systems thinking it is an axiom that every influence is both cause and effect. Nothing is ever influenced in just one direction.
In addition, in an article in Quality Progress by Mark Paradies (Under Scrutiny) explains the psychological and philosophical limitations of cause and effect, especially as it applies to 5-Whys. The biggest drawbacks mentioned are 1) that cause and effect does not help investigators go beyond their current knowledge, 2) that cause and effect leads to the problem of "confirmation bias," and 3) that the use of cause and effect tends to lead to "single cause" answers in an increasingly complex world.
Some highly respected government investigation agencies do not routinely use the term "root cause", for example, the National Transportation Safety Board. See http://www.ntsb.gov/investigations/process.html
See also
- CausationCausationCausation may refer to:* Causation , a key component to establish liability in both criminal and civil law* Causation in English law defines the requirement for liability in negligence...
- Forensic engineeringForensic engineeringForensic engineering is the investigation of materials, products, structures or components that fail or do not operate or function as intended, causing personal injury or damage to property. The consequences of failure are dealt with by the law of product liability. The field also deals with...
- Root cause analysisRoot cause analysisRoot cause analysis is a class of problem solving methods aimed at identifying the root causes of problems or events.Root Cause Analysis is any structured approach to identifying the factors that resulted in the nature, the magnitude, the location, and the timing of the harmful outcomes of one...
- RPR Problem DiagnosisRPR Problem DiagnosisRPR is a problem diagnosis method specifically designed to determine the root cause of IT problems.- Overview :RPR deals with failures, incorrect output and performance issues, and its particular strengths are in the diagnosis of ongoing & recurring grey problems...