It is a fact and often a regulatory requirement that one has to demonstrate that an apparatus is capable of providing the intended and expected outcome. A simple and common example of this requirement is the calibration of a laboratory weighing scale or balance. Initially, when a balance is purchased, and then occasionally after that, it must be calibrated against reference weights to show that the balance can provide accurate weights of the references. If the balance does not perform as expected, then it has to be adjusted accordingly. please click here for the complete article