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Root Cause Analysis Tools

  • Ishikawa Fishbone Diagram

The model introduced by Ishikawa (also known as the fishbone diagram) is considered one of the most robust methods for conducting root cause analysis. This model uses the assessment of the 6Ms as a methodology for identifying the true or most probable root cause to determine corrective and preventive actions. 

  • Five Why's

This model uses the 5 Why by asking why 5 times to find the root cause of the problem. It generally takes five iterations of the questioning process to arrive at the root cause of the problem and that's why this model got its name as 5 Whys. But it is perfectly fine for a facilitator to ask less or more questions depending on the needs

  • Failure Mode and Effects Analysis (FMEA)

FMEA is a technique used to identify process and product problems before they occur. It focused on how and when a system will fail.

  • Pareto Chart

The Pareto Chart is a series of bars whose heights reflect the frequency or impact of problems. On the Chart, bars are arranged in descending order of height from left to right, which means the categories represented by the tall bars on the left are relatively more frequent than those on the right.

  • Scatter Diagram

A scatter diagram also known as a scatter plot is a graph in which the values of two variables are plotted along two axes, the pattern of the resulting points revealing any correlation present.

  • Affinity Diagram

Also known as KJ Diagram, this model is used to represent the structure of big and complex factors that impact a problem or a situation. It divides these factors into small classifications according to their similarity to assist in identifying the major causes of the problem

  • Fault Tree Analysis (FTA)

The Fault Tree Analysis uses Boolean logic to arrive at the cause of a problem. It begins with a defined problem and works backward to identify what factors contributed to the problem using a graphical representation called the Fault Tree. It takes a top-down approach starting with the problem and evaluating the factors that caused the problem.

Image by Towfiqu barbhuiya

Managers' Talk

"Deviations are measured differences between observed value and expected or normal value for a process or product condition, or any departure from a documented standard or procedure.


From the agency's perspective, any deviation should be documented and explained. Critical deviations should be investigated, and the investigation and its conclusions should be documented.


Deviation investigation (root cause analysis) aims to determine the root cause of the problem and to provide adequate correction and preventive actions. 


There are different tools to be utilized in deviation investigations, such as 5Whys analysis  and fishbone diagram. Depending on the deviation and rigor, different tools can be used in a RCA. "

Kek Xing Yi | Head of Technical Validation

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