The Crystal Ball process capability metrics are provided to support quality improvement methodologies such as Six Sigma, Design for Six Sigma (DFSS), and Lean Principles. They appear in forecast charts when a forecast definition includes a lower specification limit (LSL), upper specification limit (USL), or both. Optionally, a target value can be included in the definition.
The following sections describe capability metrics calculated by Crystal Ball. In general, capability indices beginning with C (such as Cpk) are for short-term data, and long-term equivalents begin with P (such as Ppk).