测量变化（量规R&R）对制造过程的基本影响是使过程分布看起来比实际更宽。量具偏差和线性可以改变，也可以扩大观察到的过程分布，因此，也是需要量化和控制的重要量具参数。测量过程的长期稳定性与相应的制造过程同样重要。最后，随着QS-9000的出现，这些参数的重要性得到了认可和推广。

The basic effect of measurement variation (gage R&R) on a manufacturing process is to make the process distribution appear wider than it actually is. Gage bias and linearity can shift as well as widen the observed process distribution and, thus, are also important gage parameters to quantify and control. Long term stability of the measurement process is just as important to control as the corresponding manufacturing process. Finally, the importance of these parameters has been recognized and promoted with the advent of QS-9000.