Measurement & Experimental Science
Calibration, Traceability & Reference Standards
A measurement is defensible when the instrument, calibration or check standard, method, operator, and date are traceable. Displayed precision is not evidence of accuracy by itself.
Key concepts
- Calibration compares an instrument response with a known reference
- Check standards can reveal drift between calibrations
- Instrument resolution and accuracy are different
- Traceable records make questionable data auditable
What to measure or observe
- Record instrument ID
- Record reference standard and lot where relevant
- Document pre- and post-calibration readings
- Remove instruments from service when checks fail
Common mistakes
- Trusting a meter because it shows many decimal places
- Calibrating without recording the standard
- Using expired or contaminated standards
- Mixing data from known-bad and verified instruments
Visuals this lesson still needs
- Calibration traceability chain
- Resolution-versus-accuracy graphic
- Drift check chart
- Out-of-tolerance workflow