What are common causes of variation in a process?

Common causes of variation in a process refer to the inherent fluctuations that occur naturally within any system or process. These are variations that cannot be attributed to specific external factors or identifiable causes; instead, they are the result of the complexity and dynamics of the system itself.

When a process consistently shows variation that is random and predictable, it indicates that the system is stable and functioning within its natural limits. This type of variation is considered normal and is often referred to as "common cause variation." Understanding this concept is crucial for practitioners of Total Quality Management (TQM), as it allows them to distinguish between natural, ongoing variation and variation that is caused by specific, identifiable changes or issues.

In contrast, the other options relate to variations that can often be tied to particular events or changes within the process, rather than existing as inherent fluctuations. For example, specific incidents or situations may cause disruptions or deviations from expected performance, while changes in standards can create new expectations that do not align with past performance. Established control measures may help mitigate variations but do not directly describe the inherent variability present in the process.