Root Cause Analysis is a useful process for understanding and solving a problem. As an analytical tool, Root Cause Analysis is an essential way to perform a comprehensive, system-wide review of significant problems as well as the events and factors leading to them.
Root Cause Analysis (RCA) is a technique that helps you answer the question of why the problem occurred in the first place. Root Cause Analysis aims to identify the origin of a problem. It uses a specific set of steps to find the primary cause of the problem so that you can: Determine what happened, Determine why it happened & Figure out what to do to reduce the likelihood that it will happen again.
PRINCIPLES
- Focusing on corrective measures of root causes is more effective than simply treating the symptoms of a problem or event.
- RCA is performed most effectively when accomplished through a systematic process with conclusions backed up by evidence.
- There is usually more than one root cause for a problem or event.
- The focus of investigation and analysis through problem identification is WHY the event occurred, and not who made the error.
GOALS
- The primary goal of using RCA is to analyze problems or events to identify: What happened
- How it happened
- Why it happened…so that
- Actions for preventing reoccurrence are developed
THREE BASIC TYPES OF CAUSES
1. Physical Causes
- Tangible, material items failed in some way (for example, a water ingress alarm stopped working).
2. Human Causes
- People did something wrong or did not do something that was needed. Human causes typically lead to physical causes (for example, no one checked the alarm circuit, which led to the sensor failing).
3. Organizational Causes
- A system, process, or policy that people use to make decisions or do their work is faulty (for example, no one person was responsible for sensor maintenance, and everyone assumed someone else had checked).
Root Cause Analysis (RCA) represents comprehensive investigation, assessment, evaluation, and correction. There are many types of investigative procedures used to carry out Root Cause Analysis.
There are 7 steps in the Root Cause Analysis process which are as follows:
1. Problem Selection:
A business always has problems so all that is required is to order them on the basis of risk to the organization and deal with the most urgent ones first.
2. Problem Statement:
Be precise in the selection, keep to a tight definition of the problem and make sure that the problem has a potential solution.
3. Identify Possible Causes:
Put a team together and using the problem statement start by asking ― why? it happened. Asking ―why?‖ 5 times is a good rule of thumb to follow as it often gets you to the root causes. Then debate and choose the available corrective actions for each of the selective root causes. Keep the focus on these root causes as it is the best way to resolve or reduce the problem.
4. Implement the Corrective Actions:
Implement the Corrective and Preventive Actions making sure to communicate them to all involved. Clearly communicate the reasons, benefits, and required time lines. Don’t miss out on anybody.
5. Analyze Effectiveness:
Review the results of the Corrective Actions. Modify the corrective actions if you think that it is required. You may need to try a different approach if they don’t resolve the problem and if the corrective actions are not effective you will even need to completely review the root causes.
6. Update Procedures:
Write up the new documents and determine who needs to be retrained, making sure that nobody is missed out. Check to see whether the new procedures could also be applied to other areas such as a production line in a different factory but using the same equipment.
7. Check and Control:
Check to make sure that the new procedures are followed and are effective in fixing the issues. Revisit the issue again in, say, 3 and 6 months time to ensure that they are still in place and being followed.
TYPES OF ROOT CAUSE ANALYSIS
- Brainstorming Technique
- Fishbone/Ishikawa diagram
- 5W and 1H Techniques
- Corrective action and Preventive action (CAPA)
- Affinity Diagrams
- Pareto Diagram
- Failure Mode and Effects Analysis (FMEA)
1. Brainstorming Technique
This is one of the creative, problem-solving methods that allow people to come up with suggestions/ideas that could help, solve the problem, or help to identify the root – cause of the problem.
- A meeting with the cross-functional team may be called to identify the root cause, of such a brainstorming session.
- Relevant people will be asked to think and their views of the problem and suggest their views to reach the root cause, and solve the problem.
- All views and suggestions shall be analyzed to identify the cause of the problem.
2. Fishbone/Ishikawa Diagram
- The fishbone diagram identifies many possible causes for an effect or problem.
- It can be used to structure a brainstorming session.
- The Fishbone diagram includes the potential cause of the problem and is used in order to find the real causes.
ALSO READ: Root Cause Analysis and its Implementation
3. 5W and 1H Techniques
- 5W1H (who, what, where, when, why, how) is a method of asking questions about a process or a problem taken up for improvement.
- Four of the W’s (who, what, where, when) and the one H is used to comprehend for details, analyze inferences and judgment to get to the fundamental facts and guide statements to get to the abstraction.
- The last W (why) is often asked five times so that one can drill down to get to the core of a problem.
- 5W1H of Six Sigma explains the approach to be followed by exactly understanding and analyzing the process, project, or problem for improvement.
4. Corrective Action and Preventive Action (CAPA)
It is an extension of root cause analysis. The first goal of CA is to find the root cause, base event or error that preceded the problem. The second goal is to take action directed at the root cause or error.
PREVENTIVE ACTION
It is similar to Lessons Learned/ Read Across. PA resembles the replication activity of design for six sigma (DFSS). Another PA in industry is Yokaten, a Japanese term used by Toyota, describing a sharing across the organization. The primary goal of PA is to inform an organization and prevent the problem from returning to other facilities lines or products.
5. Affinity Diagrams
- The final root cause analysis tool is affinity diagrams. Often the output from a brainstorming session, an affinity diagram can be used to generate, organize, and consolidate information related to the issue in question.
- After ideas have been generated, they can be grouped according to their similarity to identify the major causes. An affinity diagram should be used to stimulate discussion about a problem or issue, opening up possibilities for improvement or solution.
6. Pareto Diagram
- A Pareto chart is a histogram or bar chart combined with a line graph that groups the frequency or cost of different problems to show their relative significance. The bars show frequency in descending order, while the line shows cumulative percentage or total as you move from left to right.
- Pareto charts are one of the seven basic tools of quality described by quality pioneer Joseph Juran. Pareto charts are based on Pareto’s law, also called the 80/20 rule, which says that 20% of inputs drive 80% of results. Of course, it may take asking why more than five times to solve the problem the point is to peel away surface-level issues to get to the root cause.
7. Failure Modes and Effects Analysis (FMEA)
- FMEA is a well-defined tool that can identify various modes of failure within a system or process. In many companies, if a major problem is detected in the process or product, the team is required to review any existing FMEAs in relation to the problem.
- The team should determine if the problem or effect of the failure was identified in the FMEA and if it was, how accurately the team evaluated the risk. If the problem is not included in the FMEA, the team should add any known information and then complete the following steps:
- List the current problem as a failure mode of the design or process.
- Identify the impact of the failure by defining the severity of the problem or effect of failure.
- List all probable causes and how many times they occur.
- When reviewing a process FMEA, review the process flow or process diagram to help locate the root cause.
- Next identify the Escape Point, which is the closest point in the process where the root cause could have been detected but was not.
- Document any controls in place designed to prevent or detect the problem.
- List any additional actions that could be implemented to prevent this problem from occurring again and assign an owner and a due date for each recommended action.
- Carry any identified actions over to the counter-measure activity of the RCA.
CASE STUDIES OF ROOT CAUSE ANALYSIS
CASE STUDY-1
Problem
A drug has been doing badly in the last few weeks, the root cause analysis revealed that the cause is related to non-optimum storage temperature which happened due to starting of the summer.
Solution
The solution will be using a refrigerator to store this drug even while shipping it.
CASE STUDY-2
Problem
A broken wrist hurts a lot but the painkillers will only take away the pain not cure the wrist; you will need a different treatment to help the bones to heal properly.
Solution
In this example, the problem is a broken wrist, the symptom is pain in the wrist and the root cause is broken bones. So, unless the bones are mended, the pain will not be cured.
CONCLUSION
- Root cause analysis is a methodology that needs to know the first action that leads to a sequence which in turn leads to a problem and finds a way to solve the problem.
- Corrective action must start with an investigation into the root causes of the problem.
- Root cause analysis eliminates the underlying cause of a non-conformity rather than merely addressing the symptoms of the problem.
- Without dealing with the root cause, the corrective action will be ineffective and the problem will recur.
- Useful RCA tools include the 5 why analysis and the cause-effect diagram.
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