Despite a persistent and incremental march toward automation, people are still necessary for much of manufacturing. Perhaps that will always be true for certain segments. Understanding variation is important whether the process is manual, automated or, especially, an amalgam of the two. We seek to understand the individual contributions of the processes to total variation. We do this via measurement systems analysis (MSA), and one technique associated with this is gauge repeatability and reproducibility, or gauge R&R.
To know when something is not performing correctly, we need to understand the range of typical or expected performance for the system, or the variation possible in the assorted product components and processes that will ultimately constitute the system. To gain this understanding, we must take the time to understand the contributing attributes that constitute variation inherent in the system. This is understood through MSA.