st: Sensitivity and specificity graphs for binary vars

["King, Carina" <c.king09@imperial.ac.uk>]

Hi,

I have two binary variables, one being a 'gold standard' indicator of infection and the other based on a coded predictor. I have calculated the sensitivity and specificity (using -diagt-) of the coded predictor for identifying the 'gold standard' infections, but want to represent it graphically. I have looked at the ROC commands, including -roctab- and -roccomp- but don't think these are right as both my variables binary variables. My questions are whether a Detection Error Trade-Off graph is appropriate? Or is there another type of graph that would show the sensitivity and specificity well? And are they possible in Stata? 

I am using Stata SE 11

Two-way table of my data:

		Negative (gold standard) Positive (gold standard) 
Negative (coded)	542 (true neg)		9 (false neg)	
Positive (coded)	21 (false pos)		26 (true pos)	


Thanks!!


Carina King
PhD Student

The National Centre for Infection Prevention and Management,
Imperial College,
St Dunstans Road, 
London


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