[R] How to calculate the Deviance for test data based on Cox model

David Winsemius dwinsemius at comcast.net
Thu Mar 29 15:42:58 CEST 2012

On Mar 29, 2012, at 6:03 AM, ChiangKevin wrote:

> Dear List,
> If I got a Cox model based on training set, then how should I  
> calculate the Cox log partial likelihood for the test data?
> Actually I am trying to calculate the deviance on test dataset to  
> evaluate the performance of prediction model, the equation is as  
> follows: D = -2{L(test)[beta_train] - L(test)[0]}. It means using  
> the beta coefficients got from training set to calculate the  
> likelihood of test data. I know I can got log likelihood for  
> training model, but how to get it for test data?

Well, that is an equation that has some aspects familiar to many of  
us,  but it is one that does not apply to the statistical problem for  
which you propose to use it. It applies to "nested" model comparisons,  
nested both in the sense that the data is the same and the terms are  

> Any package or function can do that? Thanks. 		 	   		
> 	[[alternative HTML version deleted]]

I think you need to seek statistical consultation.


David Winsemius, MD
West Hartford, CT

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