Hello,
I have a little mathematical problem with the terms negative likelihoo-ratio
and negative post-test odds.
1. In my opinion the LR can be calculated by post-test odds/pre-test odds.
2. If this is correct, this formule must be applicable for both the pos. and
the neg. LR.
3. Following, the negative post-test odds have to be the false negative
divided by the true negative tested persons. In words the neg. post-test
odds is the chance of being ill though having a negative test result.
The problem is, that I found in the literature different definitions of the
term neg. post-test odds. Some authors write that the neg. post-test odds
describe the chance of not having the disease, when the patient has a neg.
test result. Others write, that the post-test odds is the chance of having
the disease although the test result is negative.
Who is right? Thanks for your help.
Christian
.....................
Christian Sellenthin
Bleichstr. 30/3
89077 Ulm
tel (0731) 33560
mobil (0170) 2146394
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http://www.uni-ulm.de/~s_cselle
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