I think that your data is censored, not truncated.
For a fault introduced 1/2005 and erased 2/2006, duration = 13 months
For a fault introduced 4/2010 and still in existence at the last observation 12/2010,
duration> 8 months.
For a fault introduced before 2004, erased 3/2005, in a machine installed 2/1998, the
duration is somewhere between 15 and 87 months.
For a fault introduced before 2004, smachine installed 5/2000, still present 11/2010 at
last check, the duration is > 126 months.
For type=interval2 the data would be (13,13), (8,NA), (15,87), (126, NA).
Terry T.
On 11/14/2013 05:00 AM, r-help-requ...@r-project.org wrote:
Hi,
I would like to know how to handle truncated data.
My intend is to have the survival curve of a software fault in order
to have some information
about fault lifespan.
I have some observations of a software system between 2004 and 2010.
The system was first released in 1994.
The event considered is the disappearance of a software fault. The
faults can have been
introduced at any time, between 1994 and 2010. But for fault
introduced before 2004,
there is not mean to know their age.
I used the Surv and survfit functions with type interval2.
For the faults that are first observed in 2004, I set the lower bound
to the lifespan
observed between 2004 and 2010.
How could I set the upper bound ? Using 1994 as a starting point to not seems
to be meaningful. Neither is using only the lower bound.
Should I consider another survival estimator ?
Thanks in advance.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
