The principle of standard work is part of the foundation of the Toyota Production System. Performing work steps in exactly the same method from one unit to the next results in stability and reduces process variability. The quality output from a standard method will be consistent from piece to piece.
When a problem does occurs, comparing the documented standard work to the observed process method can quickly identifies opportunities for errors. The supervisor, team leader or quality auditor should be able to access the standard work documentation at each workstation for every process throughout the plant. Observing several cycles will confirm if the method is constant. Emphasis on strict adherence to the established standard work is mandatory.
Lean challenge for today. Go to gemba and observe the process at a random workstation. Does this workstation have a current copy of the standard work method? Is the operator following the steps exactly as described? Is the process steps repeated exactly the same from piece to piece?
If you answered no to any of these questions, fix it. Fix it right now. Do not add it to your to-do-list. Do not delegate it. Roll up your sleeve and work with the operator to fix it today.