The closeness of agreement between a measured value and the true or accepted reference value. Accuracy reflects how correctly an instrument reports the actual quantity being measured.
Accuracy is one of the most fundamental concepts in metrology and calibration. It describes how close a measurement result is to the true value of the quantity being measured. An instrument with high accuracy produces readings that are very near the accepted reference value, while an instrument with poor accuracy consistently deviates from it.
Accuracy is often confused with precision, but the two are distinct. A measurement system can be precise (producing tightly clustered results) without being accurate (those clustered results may be far from the true value). In calibration, accuracy is evaluated by comparing the instrument's readings against a higher-accuracy reference standard with known traceability to national or international standards such as NIST.
In calibration management, maintaining accuracy is critical because measurement errors propagate through manufacturing, quality control, and compliance processes. Organizations must define acceptable accuracy limits for each instrument, calibrate at appropriate intervals, and document results. When an instrument falls outside its specified accuracy range, it is declared out-of-tolerance and may require adjustment or replacement to prevent defective products or invalid test results.
Accuracy in calibration refers to how close a measured value is to the true or accepted reference value. It is determined by comparing an instrument's readings against a traceable reference standard during calibration.
Accuracy describes closeness to the true value, while precision describes the consistency of repeated measurements. An instrument can be precise but inaccurate if it consistently reads the same wrong value.
Measurement accuracy is improved through regular calibration against traceable standards, environmental controls, proper instrument handling, and applying correction factors when systematic errors are identified.
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