Regular measurement is a proven way to do this. These are just a few of the questions you should have at this time. While the specific answers may vary a bit depending on your property and organization, some basics remain constant. Any effective measurement must meet certain criteria. It must be consistent, focused, and objective.
Consistency requires that measurement follow certain guidelines.
Conditions and parameters must be constant for each measurement. This includes the qualifications and characteristics of the person or persons doing the measurement, and the actual conditions under which they make the measurement. Any change in the standard being measured requires a corresponding change in the measurement tool. An effective measurement system must focus on the specific standards to which employees have been trained. Employees must be trained to perform tasks exactly to the stated standard, and all measurement must evaluate the standard exactly as it was trained and exactly as it is performed.