Impact of the Measurement System on Process Capability
- When a process is not capable, most organizations start to
scramble to improve the process. But it could be that the process is
fine and it is the measurement system variation that is leading us
to think we have a poor process. We could be wasting time trying to
reduce the process variation when the first thing we should be
working on is the measurement system.
- When the percentage of the total variation that the measurement
system takes up is very low (such as 20%), we don't see much of an
impact on the process capability. But once the measurement system
starts to take up a great deal of the total variation, then our view
of our capability is seriously distorted by the impact of the
measurement system variation. We could have a capable process, but
get a capability number that indicates it is not.