Intro to 5 Common RCA Tools and Techniques

The BlueDragon team has decades of experience solving the most complex people problems. In this blog, the BlueDragon team offers practical insights on some of the most commonly used RCA tools and techniques.  We also discuss how each RCA tool can be misunderstood or not used properly.


1. The 5 Whys – One of Most Misunderstood RCA Tools

The 5 Whys is a technique rather than a methodology.  It is the most simple of the Socratic questions.  The 5 Why questioning technique and other Socratic questions are the primary means to conduct cause and effect analysis.

The premise of this technique is asking “why” five times to get to the deepest-seated cause of that line of inquiry. By continuously asking why, we uncover deeper layers of causes beyond the obvious symptoms.

Limitations and Considerations

A limitation of the 5 Why questioning technique is that it is often used as a stand-alone RCA tool or methodology.  Consider that each 5 Why sequence is a line of inquiry.  It takes a considerable number of lines of inquiry to be able to develop the confidence that our analysis has identified the root causes.  RCAs conducted in the Energy sector require 30 or more lines of inquiry before we are confident in our results.

Another misconception is that the “5” in 5 Whys is applicable to people problems.  The technique was developed for automobile manufacturing in the 1930s. When applying this Socratic questioning technique, the facilitator may indeed go way past 5 questions.  In one RCA conducted by the author, a single line of inquiry used 27 Socratic why questions.

2. The Fishbone Diagram (Ishikawa) – One of the Simplest RCA Tools

The Fishbone Diagram, also known as an Ishikawa diagram, is one of the most widely recognized of the RCA tools from the previous century. It helps us to brainstorm and visually organize potential causes of a problem, making it easier to identify the underlying issues.  The “bones” on the fishbone remain very useful in prompting us to look at the problem from different perspectives. However, the chart itself is not useful for a complex RCA.

There are a number of pre-established bones (themes) that have proven to be good starting points:

  1. Themes used in operating and chemical plants: Man, Method, Machines, Materials, Measurement, Environment
  2. The McKinsey 7S Framework: Strategy, Structure, Systems, Shared Values, Skills, Style and Staff
  3. The 4Ps of Marketing: Product, Place, Price, and Promotion
  4. The 8Ms Used in Manufacturing: Machine, Method, Material, Man Power, Measurement, Environment, Management/Money, Maintenance
  5. The 8 Ps used in Service Industry: Product/Service, Price, Place, Promotion, People, Process, Productivity & Quality, Physical Evidence
  6. The 4Ss used in Service Industry: Surroundings, Suppliers, Systems, Skills

Limitations and Considerations

The fishbone diagram’s hierarchical structure allows teams to probe deeper into the root causes by continuously asking ‘why?’ and exploring various layers of causality.  However, the overall construct makes it very difficult to identify the root causes of a problem.

The true value of the fishbone diagram is that it prompts us to analyze a problem from different perspectives (themes or bones).  The concept fits in very well with the BlueDragon IPS holistic approach to root cause analysis. So it was very important that we keep the best element of the fishbone, which are the bones themselves (or themes).

3. Pareto Analysis – One of the Best RCA Tool for Data Analysis

Principle of the Vital Few

The Pareto principle, also known as the 80/20 rule, was first observed by Italian economist Vilfredo Pareto in 1896. Mr. Pareto noticed that approximately 80% of the land in Italy was owned by 20% of the population. He later found that this 80/20 distribution applied to various other aspects of life, such as wealth and productivity.

Pareto charts are one of the most effective RCA tools for conducting data analysis.  Multi-tiered Pareto Analysis can be used effectively on large sets of quantifiable data to bore in on the largest contributors (causes) of problems.

Conducting Pareto Analysis

Weighted Pareto charts are the preferred method in BlueDragon IPS. These charts take into account not only the frequency but also the impact or importance of each category. By also taking into account the overall impact of the causes, we can assign weighting factors the categories.  Multiplying (frequency) x (weighting factor), we calculate a new number that gives us a more nuanced view of the data.

We must exercise caution when interpreting Pareto charts, as they can sometimes lead to oversimplification of complex issues. Common misconceptions include:

  • Assuming all factors contribute equally (a low number of causes may be more impactive than a large number of minor causes).
  • Overlooking potential interactions between different factors.
  • Underestimating the importance of addressing underlying root causes rather than just symptoms.

4. Fault Tree Analysis (FTA) – The Best of the RCA Tools for Equipment Failures

Fault Tree Analysis (FTA) was originally developed in 1962 at Bell Laboratories by H.A. Watson, under a U.S. Air Force Ballistics Systems Division contract to evaluate the Minuteman I Intercontinental Ballistic Missile (ICBM) Launch Control System.

FTA is arguably one of the most effective RCA tools for engineers, project managers, and maintenance teams to determine equipment failure modes. A process of elimination is then used to rule out which failure modes are not viable options. The remaining failure modes must be addressed through corrective actions or compensatory measures.

Using Fault Tree Analysis

  • FTA is best used to analyze equipment issues, because they have a finite set of components that can fail.
  • The FTA chart can be used to develop troubleshooting plans and diagnostic manuals for equipment.
  • The FTA chart can be used as a design tool. By assigning a failure probability for each component, the overall probability of triggering the top event can be calculated using Boolean Algebra.
  • Although human error can be one of the causes of the equipment failure, FTA should NOT be used to analyze human failures vs. equipment failures.  That is because when analyzing human failures, humans can add infinite variability to any system and a Fault Tree cannot capture all the possibilities.

One word of caution: developing the Fault Tree requires input from the subject matter experts and/or the vendors for the equipment being analyzed. In BlueDragon, the results of FTA are used as insights to create lines of inquiry questions.  These questions are the starting points for cause and effect analysis.

5. Barrier Analysis – One of Best RCA Tools When Modernized

H.W. Heinrich introduced the Barrier Analysis technique in the 1930s, focusing on identifying barriers that protect targets from hazards.

In every organization, there are many administrative requirements and physical and cyber barriers in place to ensure work is performed safely and without incidents.  Knowing that a single barrier or defense may not provide sufficient protection, organizations have implemented multiple layers of barriers and requirements (i.e. defense-in-depth).  The complete set of elements that provide defense-in-depth is called our “Line of Defenses.” 

Here are the components that make up our “Line of Defenses.”   

  • Administrative Requirements: the applicable regulations, programs, policies and procedures in place to manage the activities being conducted at the place of business. Administrative defenses include industry guidelines, standard operating procedures and training that ensure safe practices are followed.  
  • Physical Barriers: barriers in place to keep us safe from hazards. These barriers physically separate the target from the hazard, providing a tangible form of protection. Examples include Personnel Protective Equipment (PPE), lead shielding, fire doors, engineered safety features walls, fences, and guardrails.  
  • Virtual Barriers: cyber barriers are in place to help us perform work and safeguard us against the loss of valuable information. These include firewalls, software applications and other cybersecurity measures.   

Uses and Limitations

The most prevalent use of an Analysis of Defenses is after an event, incident, accident or program failure takes place.  In this application, we can identify the failure points, the at-risk behaviors and error-likely situations, deviations, non-conformances and non-compliance, and establish the applicable line of defenses in place to prevent such problems.

However, the traditional Barrier Analysis has limitations, such as stopping at the identification of the first level causal factors, which we call symptoms. In contrast, the modern Analysis of Defenses goes beyond identifying symptoms and uses cause and effect analysis to uncover the root causes of breakdowns in the line of defenses. The document also expands the view of hazards beyond the traditional categories, including non-physical threats like regulatory non-compliance, cyber-attacks, and skill shortages.

Summing up

Considering all points, the 7 powerful problem-solving root cause analysis tools provide a comprehensive set of techniques that can help identify and address the underlying issues leading to problems in various situations. By using these tools effectively, organizations and individuals can gain valuable insights into the root causes of their problems, leading to more effective solutions and long-term improvements. With the right application of these tools, you can systematically address issues and prevent them from recurring, ultimately fostering a culture of continuous improvement and success.


About the Author:

Rob De La EspriellaBD3, CEO and Founder, BlueDragon IPS

Deming Prize winning team member and pioneering Nuclear Quality Assurance expert Rob De La Espriella draws from four decades of experience in the commercial nuclear power sector and the nuclear weapons complex to offer deep insights into Root Cause Analysis and Total Quality Management. Rob is a leading expert in solving complex human-centric problems in our modern work environments, and has re-defined how organizations solve complex problems with the BlueDragon Integrated Problem-solving System (IPS), the first universal problem-solving system that can be applied to all regulated industries.  Rob is a former nuclear submarine officer, a decorated Resident Inspector with the US Nuclear Regulatory Commission, and a senior manager at commercial nuclear power plants. He was also on the Florida Power & Light team that won the Deming Prize from Japan.  Since 2007, he has been a Senior Policy Advisor for the Department of Energy and their contractors, helping solve some of their most complex issues.  Rob is a adjunct professor at Endicott College in Beverly, MA, and in 2023, he was accepted into the Forbes Business Council and is a Forbes contributor.

© 2024 DLE Technical Services, LLC. All rights reserved.

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