What does "process capability" refer to in Six Sigma?

In Six Sigma, "process capability" specifically refers to the ability of a process to produce output that meets predefined specification limits. This concept is critical in quality management as it determines how consistently a process can perform according to its desired objectives and standards. Essentially, it quantifies how much variation exists in the output of a process relative to the specifications set for it.

When evaluating process capability, practitioners typically analyze variation in output through statistical measures like Cp and Cpk, which help in understanding how well the process is centered around the target value and how much it varies. If a process operates within its capability limits, it is considered stable and reliable, thus fulfilling customer expectations for quality and performance.

While the ability to meet customer demands can be related to process capability, it encompasses broader aspects such as timeliness and service quality, which go beyond just the variability in product outputs. The speed of process execution and the cost-effectiveness of a process, while important metrics in operational efficiency, do not directly address the notion of capability concerning meeting specification limits. Hence, understanding process capability is fundamental to improving process performance and ensuring high quality in outputs.