[R] Use of survreg.distributions

Terry Therneau therneau at mayo.edu
Fri Apr 25 14:46:45 CEST 2008


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I am using survreg(Surv()) for fitting a Tobit model of left-censored 
longitudinal data. For logarithmic transformation of y data, I am trying use 
survreg.distributions in the following way: 
tfit=survreg(Surv(y, y>=-5, type="left")~x + cluster(id), dist="gaussian", 
data=y.data, scale=0, weights=w) 
my.gaussian<-survreg.distributions$gaussian
my.gaussian$name="lognormal"
my.gaussian$dist<-my.gaussian
tfit=survreg(Surv(y, y>=-5, type="left")~x + cluster(id), dist=my.gaussian, 
data=y.data, scale=0, weights=w) 
 
If I run these codes then I got the following error message, 
 
Error in survreg(Surv(y, y >= -5, type = "left") ~ x +  :
Invalid distribution object

Does anybody can help me in identifying the error(s) in these code please? 
 
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  Can you tell us what you are trying to do?  
  Your first model was a fit of y ~ x + eps, eps ~ Gaussian.  If what you want 
is log(y) ~ x + eps, then all that you need do is use dist="loggaussian" in the 
survreg call.  (Or 'lognormal'; which is the same distribution.)
  
  	Terry Therneau



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