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It is now becoming recognized in the measurement community that it
is as important to communicate the uncertainty related to a
specific measurement as it is to report the measurement itself.
Without knowing the uncertainty, it is impossible for the users of
the result to know what confidence can be placed in it; it is also
impossible to assess the comparability of different measurements of
the same parameter. This volume collects 20 outstanding papers on
the topic, mostly published from 1999-2002 in the journal
"Accreditation and Quality Assurance." They provide the rationale
for why it is important to evaluate and report the uncertainty of a
result in a consistent manner. They also describe the concept of
uncertainty, the methodology for evaluating uncertainty, and the
advantages of using suitable reference materials. Finally, the
benefits to both the analytical laboratory and the user of the
results are considered.
Metrological traceability of chemical measurement results means the
establishment of a relation to metrological stated references
through an unbroken chain of comparisons. This volume collects 56
outstanding papers on the topic, mostly published in the period
2000-2003 in the journal "Accreditation and Quality Assurance."
They provide the latest understanding, and possibly the rationale
why it is important to integrate the concept of metrological
traceability including suitable measurement standards such as
certified reference materials, into the standard measurement
procedures of every analytical laboratory. In addition, this
anthology considers the benefits to both the analytical laboratory
and the user of the measurement results.
Validationofmeasurementmethodshasbeenusedforavery ciated
measurement uncertainty? The answer must be: no.
longtimeinchemistry. Itismostlybasedontheexamination
Therecanneverbeamechanismorrecipeforproducing - of a measurement
procedure for its characteristics such as tomatically 'valid'
results because one can never eliminate precision, accuracy,
selectivity, sensitivity, repeatability, re- theskills,
theroleandtheresponsibilityoftheanalyst. producibility,
detectionlimit, quanti?cationlimitandmore. ISO 9000:2000, item 3.
8. 5 de?nes validation as 'con?r- When focussing on quality
comparability and reliability mation by examination and provision
of objective evidence in chemical measurement, the ?elds of
interest to this Jour- that the requirements for an intended use
are ful?lled'. The nal, one stumbles into various interpretations
of the term revised edition of the VIM ('VIM3'), is likely to
?ne-tune validation. It is one more example of a term which is used
thisde?nitionoftheconcept'validation'tobe'con?rmation sometimes
very consistently, sometimes very loosely or in- through
examination of a given item and provision of - deed ambiguously.
Since the term is very common in the jective evidence that it
ful?lls the requirements for a stated chemical community, it is
important that its meaning be intendeduse'. nd clear. Turning to
the 2 edition of the International Vo- Lookingatsimplepractice,
manypeoplearelookingfor cabulary of Basic and General terms in
Metrology (VIM) aformaldecisionthatagivenmeasurementmethod automat-
(1993), surprisingly we do not ?nd a de?nition. Webster's ically
gives them 'valid' i. e. reliable results. One wonders Dictionary
of the English language (1992) tells us that val- what this has to
do with 'stated intended use'. Reliab- idation is 'making or being
made valid'. Obviously valida- ity clearly is a property of a
measurement result.
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