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HOW to use str() after the survivalROC (or another library in R) to get optimal cut-off values

2 messages · Prof. Mario Petretta, Joshua Wiley

#
I have the same problem of a previous request

HOW to use the survivalROC (or another library in R) to get optimal  
cut-off values?

I want to use the time-dependent survivalROC package.according to  
the,reference
material,it only gives a partial set of ordered cut-off values .eg.
--------------------------------------------------------------------------------

data(mayo)
str(mayo)
attach(mayo)
ROC.1=survivalROC(Stime=time,status=censor,marker=mayoscore4,predict.time=365,lambda=0.05)
str(ROC.1)

plot(ROC.1$FP, ROC.1$TP, type="l", xlim=c(0,1), ylim=c(0,1),    
xlab=paste( "FP", "\n",
"AUC = ",round(ROC.1$AUC,3)),   ylab="TP",main="Mayoscore 4, Method =  
NNE \n Year = 1")
abline(0,1)

List of 6
$ cut.values : num [1:313] -Inf 4.58 4.9 4.93 4.93 ... *only 5 values

* $ TP          : num [1:313] 1 0.999 0.999 0.999 0.998 ...

  $ FP          : num [1:313] 1 0.997 0.993 0.99 0.987 ...
  $ predict.time: num 365
  $ Survival    : num 0.93

  $ AUC         : num 0.888

--------------------------------------------------------------------------------
In particular I'm unable to see and print all values after str(ROC.1)
and NOT only the 5 values listed above in the example in order to to  
get optimal cut-off values

Thank you very much!



Mario Petretta
Dipartimento di Medicina Clinica Scienze Cardiovascolari e Immunologiche
Facolt? di Medicina e Chirurgia
Universit? di Napoli Federico II
081 - 7462233



Mario Petretta
Dipartimento di Medicina Clinica Scienze Cardiovascolari e Immunologiche
Facolt? di Medicina e Chirurgia
Universit? di Napoli Federico II
081 - 7462233
#
Hi Mario,
On Sun, Dec 5, 2010 at 10:11 AM, <petretta at unina.it> wrote:
I'm not exactly sure how to parse that sentence.  Do you mean you are
trying to follow the reference, but only get a partial set of cut-off
values?  Or do you mean that according to the reference, it only gives
a partial set of ordered cut-off values?
this prints the str()ucture of the ROC.1 object to the console so you
can see how the object is stored in R
This is the output you should have gotten from str(ROC.1)
Is this what you are looking for?

ROC.1[["cut.values"]]

or are you have some other problem?
--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/