Thank you David!
On Wednesday, February 14, 2018, 6:05:46 PM PST, David Winsemius
<dwinsem...@comcast.net> wrote:
> On Feb 14, 2018, at 5:26 PM, David Winsemius <dwinsem...@comcast.net> wrote:
>
>>
>> On Feb 13, 2018, at 4:02 PM, array chip via R-help <r-help@r-project.org>
>> wrote:
>>
>> Hi all,
>>
>> The survdiff() from survival package has an argument "rho" that implements
>> Fleming-Harrington weighted long rank test.
>>
>> But according to several sources including "survminer" package
>> (https://cran.r-project.org/web/packages/survminer/vignettes/Specifiying_weights_in_log-rank_comparisons.html),
>> Fleming-Harrington weighted log-rank test should have 2 parameters "p" and
>> "q" to control the weighting for earlier vs later times in the follow-up.
>>
>> For example, setting rho=1 in survdiff() uses the Peto-Peto modification of
>> Gehan-Wilcox weights, which I can confirm by setting p=1 & 1=0 in comp()
>> from survminer package. similarly rho=0 is equivalent to p=0 & q=0
>>
>> I am interested in putting more weights on survival difference in later
>> follow-up time. According to comp() from survminer package, that would set
>> p=0 & q=1 for Fleming-Harrington weights.
>>
>> My question is how I can do the same by setting certain values for "rho" in
>> the regular survival() function?
>
> I think that survdiff uses a different version than what you have found. The
> G-rho family weights are:
>
> w_j = [Sˆ(tj)]^ρ
>
> So rather than two parameters on S(t) and (1-S(t)) as in the p,q version, you
> only have one parameter applied to S(t). This class handout says that the
> G-rho,gamma weighting scheme is not available in survdiff.
>
Forgot to paste the link:
http://www.ics.uci.edu/~dgillen/STAT255/Handouts/lecture4.pdf
> --
> David Winsemius
> Alameda, CA, USA
>
> 'Any technology distinguishable from magic is insufficiently advanced.'
> -Gehm's Corollary to Clarke's Third Law
David Winsemius
Alameda, CA, USA
'Any technology distinguishable from magic is insufficiently advanced.'
-Gehm's Corollary to Clarke's Third Law
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
