Definition
The "process voice" is used to reflect the actual capabilities and performance of the process.
In detail
Voice of Process (VOP) is the concept of using data to reflect a process's actual capability and performance, as opposed to Voice of the Customer (VOC); the "VOP" in the Ideation course means Voice of Product, which is a different meaning, so be careful to distinguish them. It helps an organization understand the true state of a process and identify variation and Muda. Combining VOP with VOC allows one to judge whether a process meets customer needs. VOP is usually quantified through tools such as Statistical Process Control (SPC). VOP outputs include process capability index (Cpk; within DBS, Cp refers specifically to Certified Practitioner and is not used as a statistical abbreviation), defect rate, and other data.
Example in practice
A factory receives customer complaints about large product dimension deviations. The quality team collects production data, calculates process capability indices, and finds Cpk below 1.0, indicating insufficient process capability. By analyzing VOP data, the team identifies equipment wear issues and performs preventive maintenance. After improvement, Cpk rises to 1.33, and customer complaints decrease. VOP provides objective evidence for problem-solving.