DMAIC approach to define, measure, analyze, implement, and control variation
BioPharm International. 2008 Nov;21(11);54–60.
Process capability is defined as the "quantifiable measure of a process. For the qualitative assessment of an organization". In Six Sigma Process capability (Cp) or process capability index (Cpk) determine whether the process is capable and is the process acceptable. Process capability is determined by the upper and lower specification limits and standard deviation a process operating at Six Sigma level has a low degree of variation and a process capability value of 2.
Process capability and Statistical Process Control
Process capability values for processes at sigma level 3 to 6. A Cp value less than 1 has a large degree or variance and is not a capable process.