Pp

process performance

Pp = (USL − LSL) / (6 · σ_overall)

Pp is like Cp but uses the overall standard deviation of all values, so it includes shifts and drift between subgroups. It describes the long-term performance the customer actually sees.

Calculate it

Process Capability & Control Charts: Cp, Cpk, Pp, Ppk, PPM and confidence intervals with X-bar/R, X-bar/S or I-MR charts and all 8 Nelson rules.

Related terms

• Ppk: process performance index
• Cp: potential process capability
• Sigma overall: long-term standard deviation