Process Capability (Cp, Cpk) and Process Performance (Pp, Ppk) – What is the Difference?

In the Six Sigma quality methodology, process performance is reported to the organization as a sigma level. The higher the sigma level, the better the process is performing.
Another way to report process capability and process performance is through the statistical measurements of C_p, C_pk, P_p, and P_pk. This article will present definitions, interpretations and calculations for C_pk and P_pk though the use of forum quotations.

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