What is calibration of measurement tools?

• A. Cleaning instruments with solvent.
• B. Replacing batteries.
• C. Training operators on how to use them.
• D. Verifying instruments against known standards and adjusting as needed to ensure accuracy.

Answer: (D)

Calibration is the process of verifying that a measurement tool gives readings that match a known reference standard and making adjustments so those readings are accurate. Over time tools can drift due to wear, temperature changes, or normal use, so comparing their output to a traceable standard ensures the measurements you rely on are trustworthy. When a discrepancy is found, you adjust the instrument or apply a correction factor, then re-check with the standard to confirm the accuracy within the required tolerance, and you document the results. This is different from simply cleaning the instrument, which removes dirt but doesn’t certify measurement accuracy; replacing batteries, while important for operation, does not guarantee measurement accuracy; and training operators on use helps avoid user error but does not calibrate the instrument itself.