Good Day All, I am working with a diagnostic test and comparing the new test to an old test. Normally I would be able to calculate sensitivity and specificity quite easily. However, the 'gold standard' that I am comparing my new diagnostic with is really 'gold-plated' in that sometimes the 'gold standard' fails completely and I have no data from the 'gold standard' but I might have data from the diagnostic test. Of course sometimes my new diagnostic fails but I have data from my 'gold standard' To me this really starts moving towards classification but I cannot seem to find the appropriate calculations. Can someone point me to some web resources to determine the appropriate method to be able to deal with the NULLs ? Resources within the medical realm would be better (because the rest of the folks would understand them better) but not required. -- - Don Donald Catanzaro PhD dgcatanzaro@gmail.com 16144 Sigmond Lane Lowell, AR 72745 479-751-3616 [[alternative HTML version deleted]]
This is not an R question. Post elsewhere. Better yet, contact a local statistical consultant. -- Bert On Wed, Aug 28, 2013 at 7:18 AM, Donald Catanzaro <dgcatanzaro at gmail.com> wrote:> Good Day All, > > I am working with a diagnostic test and comparing the new test to an old > test. Normally I would be able to calculate sensitivity and specificity > quite easily. > > However, the 'gold standard' that I am comparing my new diagnostic with is > really 'gold-plated' in that sometimes the 'gold standard' fails completely > and I have no data from the 'gold standard' but I might have data from the > diagnostic test. Of course sometimes my new diagnostic fails but I have > data from my 'gold standard' > > To me this really starts moving towards classification but I cannot seem to > find the appropriate calculations. > > Can someone point me to some web resources to determine the appropriate > method to be able to deal with the NULLs ? Resources within the medical > realm would be better (because the rest of the folks would understand them > better) but not required. > > -- > - Don > > Donald Catanzaro PhD > dgcatanzaro at gmail.com > 16144 Sigmond Lane > Lowell, AR 72745 > 479-751-3616 > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
At 15:18 28/08/2013, Donald Catanzaro wrote:>Good Day All, > >I am working with a diagnostic test and comparing the new test to an old >test. Normally I would be able to calculate sensitivity and specificity >quite easily. > >However, the 'gold standard' that I am comparing my new diagnostic with is >really 'gold-plated' in that sometimes the 'gold standard' fails completely >and I have no data from the 'gold standard' but I might have data from the >diagnostic test. Of course sometimes my new diagnostic fails but I have >data from my 'gold standard'I am not sure I completely understand the situation, my crystal ball is becoming rather opaque, but it sounds as though you are looking for some form of meta-analysis of diagnostic tests when there is no reference standard. HSROC, available from CRAN, claims to provide this although I have never used it myself.>To me this really starts moving towards classification but I cannot seem to >find the appropriate calculations. > >Can someone point me to some web resources to determine the appropriate >method to be able to deal with the NULLs ? Resources within the medical >realm would be better (because the rest of the folks would understand them >better) but not required. > >-- >- Don > >Donald Catanzaro PhD >dgcatanzaro at gmail.com >16144 Sigmond Lane >Lowell, AR 72745 >479-751-3616 > > [[alternative HTML version deleted]]Michael Dewey info at aghmed.fsnet.co.uk http://www.aghmed.fsnet.co.uk/home.html