Hello,

I have a very small data set with two diagnostic test data. One is an old test and gold standard and we want to test how good the new test is at diagnosing the same disease. Should I calculate the specificity, sensitivity, NPV, PPV, AUC or concordance? There are so many tests.


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Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input byte(id oldtest newtest)
1 1 1
2 1 1
3 1 0
4 0 0
5 1 1
6 0 0
7 0 0
8 0 1
9 1 1
end
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So far, I have used this code in Stata but I am not sure why it says "True D defined as newtest ~= 0 ", shouldn't the disease be defined by 1?

diagtest oldtest newtest

Array