  In an interlaboratory key comparison, a data analysis procedure for this
comparison was proposed and recommended by CIPM [1, 2, 3], therein the degrees
of equivalence of measurement standards of the laboratories participated in the
comparison and the ones between each two laboratories were introduced but a
corresponding clear and plausible measurement model was not given. Authors in
[4] offered possible measurement models for a given comparison and a suitable
model was selected out after rigorous analyzing steps for expectation values of
these degrees of equivalence. The systematic laboratory-effects model was then
selected as a right one in this report. Those models were all based on the one
true value existence assumption. However in the year 2008, a new version of the
Vocabulary for International Metrology (VIM) [7] was issued where the true
value of a given measurement standard should be now perceived as multi true
values which following a given statistics distribution. Applying this
perception of true values of a measurement standard with combination of the
steps in [4], measurement models have been developed and degrees of equivalence
have been analyzed. The results show that although with new definition, the
systematic laboratory-effects model is still the reasonable one in a given key
comparison.
