A discrepancy between the actual process capability and the potential process capability reveals the presence of variation within the process attributable to factors beyond inherent, common cause variation. This difference suggests that the process is not operating at its optimal level of performance. For instance, if a machine setting drifts over time, or if different operators use slightly different techniques, the actual process performance will be lower than what is theoretically achievable if the process were perfectly stable and centered.
Understanding this distinction is vital for process improvement initiatives. By recognizing that the current performance falls short of the potential, resources can be directed towards identifying and mitigating the sources of special cause variation. Historically, statistical process control methods have emphasized the reduction of such variability as a primary means of enhancing overall quality and efficiency. Minimizing this difference leads to more predictable and consistent outputs, resulting in reduced waste, improved customer satisfaction, and increased profitability.
