Digging for the Root Cause
- Publication:
- Six Sigma Forum Magazine
- Date:
- May 2008
- Issue:
- Volume 7 Issue 3
- Pages:
- pp. 19-24
- Author(s):
- Jing, Gary G.
Abstract
Many Six Sigma practitioners use the term “root cause” without a clear concept of its larger meaning, and similar situations occur in Six Sigma training programs. As a result, many practitioners overlook root causes. At the philosophical level, there is no absolute root cause in the infinite chain of causation. With this concept in mind, the challenge is to know when to stop drilling down and conclude the root cause has been reached. In Six Sigma training there are three keys that can help achieve that end: the leverage point principle, the Pareto principle, and the span of control/sphere of influence principle. Usually, it is better to focus on causes that have high leverage and high frequency and are within the span of control. Six Sigma training covers five popular identification tools, including the five whys and the fishbone. Some aspects of these tools are usually overlooked, such as when and where to stop and how to differentiate multiple causes through a weighing system that prevents loss of focus.