Which signs would indicate a need to recalibrate an instrument during fieldwork?

• A. Readings drift over time
• B. Readings differ between instruments
• C. Readings align with a known standard
• D. All of the above

Answer: (D)

In fieldwork, keeping measurements accurate means watching for signs that an instrument’s calibration might be slipping and taking action to recalibrate. If readings drift over time, the instrument’s response is changing, which introduces bias and reduces trust in the data. If readings differ between instruments, there’s an inconsistency that points to at least one device being off, so recalibration helps bring them into alignment. Even when readings align with a known standard, that shows current accuracy, but regular verification against standards is part of good practice to ensure it stays reliable over time. When you consider these possibilities together, all of these signs signal a need to recalibrate to maintain trustworthy measurements.