Defining “Root Cause”

Torbjorn Idhammar

IDCON strongly believes that one of the strongest tools for improving plant reliability and performance is the analysis of root causes of failures and then working to eradicate those failures. What is a “root cause”? It can be described as “the cause of a problem which, if adequately addressed, will prevent a recurrence of that problem.”

For example:

The situation is that a bearing has failed, and the investigation shows that it hadn’t been lubricated. Trying to figure out why it had not been lubricated led to the discovery that the grease point was missed during a survey and that it wasn’t even on the lubrication mechanic’s route sheet. Following the provided definition for root cause, this problem can be prevented very easily by simply adding the grease point to the route sheet.

However, we can elevate the definition of root cause to include “the cause of a problem which, if adequately addressed, will prevent recurrence of that problem or similar problems”. Going back to our example situation, the next question would be “why was the grease point missed in the lubrication route?”. It could have been that lubrication routes were set up by one person and then no checks or confirmation were performed to make sure that the routes were complete. This may lead to a change in the procedure for the development of lubrication routes, which will ensure that there are no other missed lubrication points in the plant and that there won’t be any in the future.

By continuing to ask the question “why”, the root cause of a problem is often identified as either a procedural shortcoming or a management issue. Addressing these root causes often requires a change of thinking and a strong effort, but the results will be much longer lasting and more valuable than correcting individual failures.