Interpretation & Calculations
A Process Performance Index. A measure of the percentage of the tolerance actually used by the sample. Smaller numbers are best.
where Pp is the Process Performance Index.
Learn more about the SPC principles and tools for process improvement in Statistical Process Control Demystified (2011, McGraw-Hill) by Paul Keller, in his online SPC Concepts short course (only $39), or his online SPC certification course ($350) or online Green Belt certification course ($499).