Root Cause Analysis (RCA)

No matter how you slice it, even with the best quality systems, training and statistical process control; all manufacturing process will experience problems such as non-conforming parts, equipment failure resulting in lost productivity or rework expenses and possible increased scrap. The real challenge is how to keep this problem to the minimum as much as you can, specially the repeated ones, that’s why RCA take place.  The goal of a Root Cause Analysis (RCA) is to get down to the true cause of the problem, the root cause.

 Root Cause Analysis by definition is a comprehensive term encompassing a collection of problem-solving methods used to identify the real cause of a problem; it is the process of defining, understanding and solving a problem. It is usually used to establishing the root causes of client discontent, or the issues gathered during the conduct of market feedback analysis regarding the product, service, or consistency. It is also considering the problems of processing highlighted during the Quality Clinic Process Charts (QCPC), vendor quality or distribution issues, deficit in business objectives like, operational margins, revenue, human resource contentment, inventory management, proficiency levels, health and safety, or enterprise environmental factors.

Repeat problems are a source of waste in manufacturing; waste that should be eliminated. Generally speaking, if we did not dig deep enough into the real cause of any problem to reach the roots it might occurs again and again.  

Many times, we may believe that the problem is resolved but in reality, we have just addressed a symptom of the problem and not the actual root cause. Correctly performed, a Root Cause Analysis can identify breakdowns in your processes or systems and determine how to prevent it from happening again.

To eliminate repeat problems an RCA is to be performed to identify what happened, why it happened, when it happened, and then determine what improvements or changes are required. Through the proper application of RCA,

Since RCA methods and tools are not limited to manufacturing process problems only there are to many industries are applying RCA methodology in various situations and are using this structured approach to problem solving.  Also, you can some tools to your everyday aspect. The point is that RCA can be applied to almost any type of problem that companies face every day.

Root Cause Analysis (RCA) is usually a step in a larger problem-solving exercise. There are multiple tools that may be used during a Root Cause Analysis. Also, several problem-solving methods that use Root Cause Analysis within their problem-solving process, such as Eight Disciplines of Problem Solving (8D), Six Sigma / DMAIC, or Kaizen.

The RCA is a critical step in each of these examples. Before RCA can be performed, the problem must be well defined. The following information must be determined and documented:

• Who discovered the problem?
• What exactly happened?
• Why it happened?
• How it happened?
• Where in the process was the problem discovered?
• When was the problem discovered?
• How many / How often does it happen?
• How was the problem detected?
• How to prevented from happening again?

The problem should be defined based on facts and data; therefore, collecting additional information and data may also be necessary to initiate interim containment or corrective actions.  Once the problem is fully described then the Root Cause Analysis phase begins.

In an RCA, basic and contributing causes are discovered in a process similar to diagnosis of disease – with the goal always in mind of preventing recurrence. By using the following tools:

The team: When appropriate, team members from the next step in the process or from other shifts.  Each member of the CFT will bring their own knowledge and view of the process

The tools: There are multiple tools that could be utilized during a Root Cause Analysis. The first step is to determine what is included and what is not included in the problem investigation.

Is/ Is Not: It may be used at different points in the RCA. It can be used while defining the problem to determine what is in scope and will be considered during the analysis and what is out of scope and will not be considered. It can also be used when planning a solution, to help the team decide what to include and what to exclude. If the boundary of the problem is not clearly defined the team may stray off the initial path and work on solving inconsequential problems.

Ishikawa Diagram (Fishbone Diagram): It is a useful tool in determining causes of a quality problem. The main sections of the diagram are used to address the 6Ms (Man, Material, Method, Machine, Measurement and Mother Nature. The diagrams are usually worked right to left, with each large “bone” of the fish branching out to include smaller bones with additional details. It is important not to limit the teams brainstorming ideas here. If an idea is in a different section of the diagram, simply list it in the appropriate section and then go back to it.

5 Whys: The 5 Whys method is simply asking the question “Why” enough times until you get through all the symptoms of a problem and down to the root cause. It is used in coordination with other analysis tools, such as the Cause and Effect Diagram, but can also be used as a standalone tool. The 5 Whys is most effective when the answers come from people who have hands-on experience of the issue being examined. The 5 Why Form can sometimes have three separate areas (or “legs”) to address the 5 Whys: Why it occurred, why it was not detected and Why our systems failed. Each area should be explored and you may have more than one causal progression for each area.

Failure Modes and Effects Analysis (FMEA): It 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.  That might 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

Action Plan: Once the team has determined the root cause using any combination of the tools listed above then they must develop the appropriate counter-measures or corrective actions. In addition, the team should develop an action plan for implementation of the counter-measures. The corrective action must be clearly defined and achievable by the team member assigned to complete the task. The action plan should also contain expected due dates for each of the corrective actions. It is often discovered that corrective actions without an owner or an expected due date seldom get completed. Occasionally the counter-measures require tasks to be completed by more than one of the team members simultaneously or in a certain order. The action plan should be used to track progress of individual action items required to complete implementation of the countermeasures.

Verification Plan: The team should also determine a validation Plan. This is used to provide a documented performance appraisal of the counter-measures effectiveness. This could entail recording data or auditing any special controls developed and implemented during the RCA exercise. Evidence should be collected to verify the effectiveness of the counter-measures or corrective actions. 

In Conclusion; Dig deep into a problem roots are the reason why we should be relentless for eliminating the real cause, which may be too far to be visibly noticed. The development of a well-planned Root Cause Analysis (RCA) process can be very valuable to any company by determining the root cause and taking action to prevent it from re-occurring. Being relentless is often not simple, because of several reasons, including constraints of resources and time. However, when the required time and efforts are spared, a root cause analysis will in fact prove to be much more advantageous. The results will improve client satisfaction, operating cost, and customer loyalty. Using of Relentless Root Cause Analysis by several organizations has produced nearly zero defects in their products.

 The lessons learned during an effective RCA can often be carried over to similar designs or processes. This should initiate a problem-solving continuous improvement mind-set to spread throughout the company.

The best examples are the world-renowned OTIS that has zero defects during 15 years, and total operator level traceability, and supply of more than 40,000 pieces of faultless Remote Load Management Units, and Siemens, whose monthly production of Power Control Centers was the greatest, with minimum issues concerning quality.

These organizations benefited because of their meticulous approach to problem solving, documenting root cause analysis outcome for further review, use of suitable corrective preventive action and fishbone diagrams, and systematic investigation by preparation of root cause analysis diagram.