What does the Cp measurement indicate?

The Cp measurement, or process capability index, is a statistical tool used to determine the potential capability of a process under ideal operating conditions. It compares the width of the process spread, represented by the process variation (the distance between the upper and lower specification limits), to the width of the natural spread of data (the process variability). When the Cp value is greater than 1, it indicates that the process has the potential to produce output that meets specifications consistently. Essentially, it provides insights into how well a process can perform relative to its specified limits, assuming it is centered between those limits.

Thus, the Cp measurement is not reflective of actual performance, which may deviate due to various factors, nor does it provide metrics about cycle times or customer satisfaction. Instead, it focuses solely on an idealized view of the process, determining how capable it is of producing outputs within specified limits if other conditions are optimized.