CPIM Practice Exam

Which is an example of a special cause of variation in a process?

1. Room temperature variations throughout the day

2. Poorly trained operators

3. Use of expired materials

4. Poor process design

The correct answer is: Use of expired materials

In the context of process variation, a special cause refers to variation that is not inherent to the process and can generally be identified and eliminated. Such variations are usually attributed to specific, identifiable factors that can lead to significant and unusual fluctuations in process performance. The use of expired materials stands as an example of a special cause of variation because it introduces a specific, identifiable reason for deviation from the expected process performance. When materials are expired, they may not perform as designed, leading to unexpected defects or failures in the process. This is a clear deviation from standard operating conditions, making the cause of variation recognizable and correctable. In contrast, the other options describe common causes of variation, which are generally part of the normal operation of a process and are more systemic in nature. Room temperature variations occur typically and are expected in many environments, poorly trained operators can lead to consistent issues over time rather than a specific incident, and poor process design reflects an ongoing structural problem that affects performance but does not represent a distinct, changeable cause of variation. All of these contribute to the baseline level of variation within a process rather than introducing one-off or irregular instances of variation.