Comparison Measurement

Comparison Measurement


the general name of measurement methods in which the quantity measured is compared with a quantity reproduced by a standard.

Comparison measurement includes (1) the opposition method, in which two quantities—the measured quantity and the quantity reproduced by the standard—act simultaneously on a comparison device, as in measuring a weight on a balance, (2) the difference method, in which the difference between quantities acts on a comparison device, for example, in comparing the lengths gage blocks on an interferometer, (3) the null method, in which the resultant effect of the comparison is zero, for example, in measuring resistance by means of a DC bridge with complete balancing, (4) the substitution method, in which the measured quantity is replaced by a quantity reproduced by the standard, for example, in weighing a body by alternately placing the body and weights on the same pan of a balance, and (5) the coincidence method, in which the difference between quantities is measured by the coincidence of marks on scales or of signals, as indicated, for example, by a vernier or stroboscope.

Comparison measurement is applicable to quantities that can be reproduced by standards. This method usually affords greater precision than indirect measurement because the error of the result is chiefly determined by the insignificant error of the standard, and the residual errors can be kept to low values.


Burdun, G. D., and B. N. Markov. Osnovy metrologii. Moscow, 1972.


References in periodicals archive ?
The display can be zeroed at any position, making comparison measurement easier.
The participation in this international comparison measurement was representing a real validation of the device and evaluated measurement uncertainty.
2 puts inspection and digital image management in the palm of your hand with three interchangeable camera head options, integrated image capture, full-motion video recording capabilities and comparison measurement features.
Research lab ChromaDex developed the standards, and in accordance with AOAC protocol, performed a single lab validation to quantify xanthones through comparison measurement of detector response factors of individual xanthones.
Electronic digital readouts moved comparators from comparison measurement to direct measurement, Mr Mason adds.
Predicting the function of new sequences by comparison measurement has been hampered by commonly utilized error-prone software.
The 10 kV reference techniques at NIST are generally only used for comparison measurement work at NIST and rarely requested for routine calibrations.
Multimeter Metex M-3860M was used for the comparison measurement.
Standardization/ recalibration makes sense only when sufficient correlation of the investigated immunoassay is achieved with the comparison measurement procedure (or sufficient specificity).
Gages are used in conjunction with electronic or dial indicators for comparison measurement or interfaced with data-collection software.
The complete comparison measurement routine was conducted at least twice for each of the NIST standards.
K4 was calibrated at the BIPM again in 2013, and its mass is well within the uncertainty of the comparison measurements with K20 performed at NIST.

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