How does verification differ from calibration?

• A. Calibration adjusts the instrument to meet standards.
• B. Verification checks current performance against acceptance criteria; calibration adjusts instrument to meet standards.
• C. Verification and calibration are the same process.
• D. Verification always reduces uncertainty; calibration never changes accuracy.

Answer: (B)

The key idea is that verification and calibration serve different purposes in ensuring measurement quality. Verification is the process of confirming that the instrument’s current performance meets predefined acceptance criteria. It’s a check of what the instrument is doing now, using known reference values, and it doesn’t change the instrument itself. Calibration, on the other hand, is about making an adjustment to the instrument so its readings align with a known standard. That adjustment fixes bias or drift, so future measurements are closer to the true values.

In practice, you verify by applying reference values and seeing if the instrument’s outputs fall within the allowed tolerance. If they do, the instrument passes verification. If they don’t, you typically proceed to calibration (or servicing) to bring the instrument back into spec. Calibration uses traceable standards and adjustments to correct the readings, whereas verification confirms the instrument remains within specified limits without changing it.

So, the best answer captures that verification checks current performance against acceptance criteria, while calibration adjusts the instrument to meet standards.