Abstract
The expression "root cause" is somewhat misleading. Many people, including Six Sigma practitioners, use it without realizing its larger context. Books on quality or Six Sigma don't always give clear descriptions of the concept of root cause. One exception is the book "Six Sigma Black Belt Handbook," which provides a list of tenets that "underpin the belief that root causes can be fixed to improve processes," citing that "they are must-be-accepted beliefs" for Six Sigma to reliably succeed. Although not many quality or Six Sigma books bother attempting to explain the true meaning of root cause, the nature of the cause-effect relationship and root cause have been widely covered at the philosophical level outside the quality arena. Although many tools can be used to identify root causes, most Six Sigma training covers five of the most popular ones that span the full spectrum from simple to complex.