In response to Roger's comment on my use of the word 'accuracy':
In naming the Steroid Accuracy Forum, I was trying to use 'accuracy' in its
normal English usage sense.
The Oxford English Dictionary at http://www.oed.com/ gives:
"the state of being accurate; precision or exactness resulting from care; hence,
precision, nicety, exactness, correctness"
This does appear to embrace precision.
I was not able to locate IUPAC's latest definition on the web, but found the
following sites which did give VIM definitions and information on 'uncertainty'.
http://physics.nist.gov/Pubs/guidelines/appd.1.html
http://physics.nist.gov/cuu/Uncertainty/basic.html
http://physics.nist.gov/Document/tn1297.pdf
http://www.sp.se/metrology/eng/terminology.htm
The VIM definition of 'accuracy of measurement' (VIM 3.5) is "closeness of
agreement between the result of a measurement and the value of the
measurand"
If I were to re-name the 'Steroid Accuracy Forum' according to proper
ISO/IUPAC/VIM metrology definitions, what should it be?
Steroid Trueness Forum
Steroid Uncertainty Forum
or ?
I want laboratories producing steroid results to understand the limitations of the
technology they use and work collaboratively (amongst themselves and with
industry) to improve comparability of results through reducing uncertainties
arising from poor analytical specificity, incorrect calibration, variability in
laboratory practice, use of reference ranges and interpretation of results.
The first two elements involve getting assays to give results that are closer to
the 'true' value (I hesitate to use the word 'true' after my lambasting in ACB
News recently, but here we go again!). The final three elements involve an
evidence-based approach and review of procedures.
Since the etymology of 'accurate' is from the Latin 'to apply care to', perhaps
this all-embracing meaning is appropriate here.
I would welcome help and advice as to how to convey this in a succinct and
straightforward way in the naming and description of the purpose of the Forum.
With regard to my use of " ... improving accuracy and precision ..." in the third
paragrah of the latest posting, I have now amended this to say "... reducing
uncertainty at low concentrations...". I hope this is acceptable.
JGM
On 29 Nov 2001, at 10:47, Roger Ekins wrote:
> I quickly glanced at Jonathan Middle's report and happened
> (regretfully) to note that his use of the term "accuracy"does not
> conform to the latest international (IUPAC) recommendations on the
> use of terms in the IVD field (on which I cannot quickly put my hand)
> in that it does not embrace "precision".
>
> I don't always agree with the findings of international committees,
> but I do in regard to IUPAC's recommended use of the word "accuracy"
> as embracing both random and systematic errors, this conforming to
> normal English usage. Otherwise one run's into absurdities such as the
> proposition that the less accurate of two methods may generally lead
> to assay results that are closer to the true value (in contradiction
> to the definition of statistical terms given in, eg, 'A Dictionary of
> Statistical Terms' by MG Kendall and WR Buckland (Hafner, New York
> 1971).
>
> Understanding the concepts underlying the words used in science is
> not a trivial matter of interest only to academics and bureaucrats but
> can have enormous practical importance - think of the controversies
> and fundamental errors relating to immunoassay design (now extending
> into the microarray field) because many scientists (including, I
> regret to say, most members of the ACB!) don't understand the meaning
> of the word "sensitivity".
>
> For a discussion of the concept of "accuracy", it's worth reading the
> Statistical Manual of the Association of Official Analytical Chemists
> by WJ Youden and EH Steiner (of which my copy, the 3rd edition, was
> published in 1975) which should, in my opinion, be required reading
> for all ACB members.
>
>
>
>
>
>
> --
> Roger Ekins
>
> Molecular Endocrinology
> University College London
============================================
Jonathan Middle, UK NEQAS Birmingham
tel 0121 414 7300 fax 0121 414 1179
This message is intended only for the above
recipient(s). The opinions expressed are
mine alone and do not necessarily represent
those of UK NEQAS Birmingham, the University
Hospital Birmingham NHS Trust or the UK NEQAS
Organisation.
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