The adjustment dilemma [calibration]

Calibration plays an important part of today´s manufacturing process, and close control is placed by the UKAS upon the measuring techniques employed by those who provide calibration services. But what controls are there covering the actual process of calibration? In a quality-driven manufacturing process, knowledge of the performance of a piece of test equipment yesterday (i.e. before it was sent for calibration) is just as important as its performance today. Having accurate, believable calibration data concerning the performance of that equipment as it was last used is every bit as important as the final calibration report