ACCURACY ,REPEATABILITY AND REPRODUCIBILITY

Accuracy
The accuracy of a test method is the proximity of different experimental results obtained in samples the same. The calculation of accuracy is given by the repeatability r and reproducibility R, both defined in ISO 5725-1. The calculation methods are given in ISO 5725-2, ISO 5725-3 and ISO 5725-4.
R r values of dissipation factor of an insulating liquid depend on the nature of the liquid tested, whether the fluid is new or used and the temperature, these values are altered and is very low (Less than 10-4), as is the case in highly insulating liquids, which are altered significantly by the impurities, handling, cleaning the test cell, and so on.

Repeatability (r)
If obtained in a laboratory two measures A and B, at room temperature, can be considered acceptable if the absolute difference !A - B! satisfies the equation:





Where
Min (A, B) is the smaller of the two values A and B.
For new insulating liquids: l== 0.2
For insulating liquids used: l= 0.1

Reproducibility (R)
If you get two different laboratories in two steps A and B, at room temperature, the above relationship is still the following valid values l
For new insulating liquids: l = 0.35
For insulating liquids used: l = 0.20

Examples of R and R
The following table gives examples of r and R values, net of inter-laboratory trials conducted with insulating mineral oil at room temperature:

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