[R] Help on extract paramters from fitted models

[Marc Schwartz]

Lisa wrote:
> Hi, I have a question about how to extract paramters from a fitted model. I
> can extract coefficients and std, but from some other statistics, I dont
> know how to extract. Can anyone help?
> 
> Here it is an example:
> 
> 
>>  coxout<-coxph(Surv(t,t.censor)~x)
> 
> 
>> coxout
> Call:
> coxph(formula = Surv(t, t.censor) ~ x)
> 
> coef exp(coef) se(coef)    z    p
> x 0.349      1.42    0.257 1.36 0.17
> 
> Likelihood ratio test=1.84  on 1 df, p=0.175  n= 200
> 
>> coxout$coef
>         x
> 0.3490500
> 
>> coxout$p
> NULL
> 
> Any convienent way to extract the LRT and the p value?  thank you!

Use the summary method for coxph objects:

   summary(coxout)$logtest["test"]

   summary(coxout)$logtest["pvalue"]

Unfortunately, this is not documented in the built-in help for the 
survival package, but you can see the structure for the summary.coxph 
method by using:

   str(summary(coxout))

?summary.coxph actually points to the structure details of a coxph 
object, rather than the summary.coxph object.

HTH,

Marc Schwartz