Re: st: R: compare median survival times? (flag: Stata 9.2/SE)

[Ronan Conroy <rconroy@rcsi.ie>]

On 11 Meith 2010, at 15:48, Martin X wrote:

> Thanks for your input, Carlo and Ronan. I agree with Ronan that the  
> code below will only compare survival functions with defined median  
> survival times. The hypothesis itself is motivated by my desire to  
> be able to say that half of group A survived 30 months and half of  
> group B survived 20 months, and the 10 month difference between A  
> and B is statistically significant. I've already used cox reg to  
> compare the survival functions (and logistic reg to compare survival  
> at a given time endpoint). Now, I just want to be able to provide  
> some "common language" results (i.e. months of survival for half the  
> group).


I agree with your desire to present the results as an effect size.  
However, picking just one point on the function may be misleading. The  
hazard ratio is a useful global measure of effect, as is Harrell's c.


Ronan Conroy
=================================

rconroy@rcsi.ie
Royal College of Surgeons in Ireland
Epidemiology Department,
Beaux Lane House, Dublin 2, Ireland
+353 (0)1 402 2431
+353 (0)87 799 97 95
+353 (0)1 402 2764 (Fax - remember them?)
http://rcsi.academia.edu/RonanConroy

P    Before printing, think about the environment




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