What does process capability refer to in Six Sigma?

Process capability in Six Sigma pertains to the ability of a process to produce outputs that consistently fall within specified limits. This concept is essential for understanding how well a process can perform in relation to its targeted specifications. A process is deemed capable if it can produce a large proportion of outputs within the defined upper and lower specification limits over time, indicating reliability and quality in production.

When focusing on process capability, practitioners often use statistical measures such as Cp and Cpk to quantify this capability. These indices help to evaluate how well the process variation is within the defined limits, illustrating both the process potential and actual performance.

The other options address aspects of process management but do not accurately define process capability. For example, frequency of outputs meeting specifications is a measure of quality but does not directly describe the inherent ability of the process. Similarly, efficiency relates more to the resource utilization and speed of a process rather than its capability. Lastly, the total number of outputs produced provides information on volume but lacks relevance in assessing whether those outputs meet the established quality standards.