Thank you. I should have mentioned that I have read the1986 Bland and Altman
paper. However, here the situation is a little bit different that what is
discussed in the paper.
In the case of B&A, each sample is analyzed twice by the two methods under the
comparison. In my case, each sample is analyzed (measured) only once using one
reference method and many times using the another (novel) one. That is why I
find it difficult adopting the B&A methodology.
P.S It is interesting to know that the 1986 B&A paper will be re-published this
August in Int J Nurs Study http://www.ncbi.nlm.nih.gov/pubmed/20430389
________________________________
From: John Sorkin <[log in to unmask]>
To: Jonathan James <[log in to unmask]>
Sent: Tue, July 13, 2010 6:26:23 PM
Subject: Re: Assessing accuracy of a measurement method
You might want to start by reading the papers by Bland and Altman
Altman DG, Bland JM (1983). "Measurement in medicine: the analysis of
method comparison studies". Statistician 32: 307–317.
doi:10.2307/2987937.
Bland JM, Altman DG (1986). "Statistical methods for assessing
agreement between two methods of clinical measurement". Lancet 1 (8476):
307–10. PMID 2868172.
Of the two, I would start with the second as it is a bit easier to
read.
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax) 410-605-7913 (Please call phone number above prior to faxing)>>>
Jonathan James <[log in to unmask]> 7/13/2010 10:02 AM >>>
Hello,
this is my first mail to allstat (although I have been reading the
archives for
a while)
I have been asked to assess the accuracy and precision of a new
measurement
method (Let's call it method B). This new method is compared to an
existing
one (A) that is considered to be "very accurage" and has its own
specifications
in terms of stdev of a single measurement. What we do is to measure
several
samples with method A and then with method B. Since A is very
expensive, only
one A measurement per case is available. Method B is cheaper, so we
measure
each sample with method B between 10 and 30 times. Another problem is
that we
are unable to find samples that would span across the entire legal
measurement
range, resulting in several samples in the first quartile of the
range, several
in the last range quartile and almost no in between.
How can I assess the accuracy and precision of method B? Any help or
link will
be appreciated.
Thank you very much
Jonathan James
P.S. This is not a homework.
P.P.S I admit, I don't know statistics well
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