Which term refers to the variation in a process that is due to natural causes?

The term that refers to variation in a process due to natural causes is known as common cause variation. This type of variation is inherent in the process and occurs under stable operating conditions, indicating that any fluctuations are expected and a natural part of the system. Common cause variation represents the baseline or predictable level of variability present in a process and typically cannot be eliminated without making fundamental changes to the system itself.

Understanding common cause variation is crucial in process improvement, as it helps differentiate between variations that are normal and those that signal deeper issues requiring investigation. This distinction informs how teams approach quality control and process enhancement.

In contrast, other options represent different types of variation. Special cause variation, for example, arises from specific, identifiable factors that can disrupt the usual process flow and lead to unexpected changes. Total variation encompasses all variability present in a process, while systematic variation refers to patterns in the data that suggest bias or trends rather than random fluctuations.