
Hello R Community,
 
I'm continuing to work through logistic regression (thanks for all the help on score test) and have come up against a new opposition.
 
I'm trying to compute Somers Dyx as some suggest this is the preferred method to Somers Dxy (Demaris, 1992).  I have searchered the [R] archieves to no avail for a function or code to compute Dyx (not Dxy).  The overview of Hmisc has mention of Dyx for the rcorr.cens function but this appears to be a misprint because the manual states the function finds Dxy.  Peng and So (1998) state that the Dyx is easily calculated in SAS (which tells me the same is possible for [R]).  
 
Yang, K., Miller, G. J., & Miller, G. state that:
 
(Tau-b)^2=Somers Dxy * Somers Dyx 
 
…so maybe an approach would be to write a function that is:
 
Somers Dyx<-(Tau-b)^2/Somers Dxy  
 
I just don't want to waste time if this is incorrect logic and/or there's an easier way to calculate this thing; perhaps there’s a ‘golden’ function already created in an [R] package that I'm overlooking.
 
Thanks in advance,
Tyler   		 	   		  
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