But it is very very unlikely to have a time with survival probability of 0.9999 in a real data set. It would be necessary huge data set. A Monte Carlo simulation could put a little more light in this issue?
2012/4/16 Frank Harrell <f.harr...@vanderbilt.edu> > Just generate some data where the estimated survival probability is 0.9999 > at > a certain time. The log-log transformation blows up. > Frank > > Enrico Colosimo wrote > > > > What are the significant problems of the log-log transformations? > > Any papers published about it? > > Enrico. > > > > > > 2012/4/14 Frank Harrell <f.harrell@> > > > >> I used log-log in my book too until Terry Therneau alerted me to the > >> significant problems this creates. In the 2nd edition it will use log > >> S(t). > >> Frank > >> > >> Paul Miller wrote > >> > > >> > Hello Drs. Colosimo and Harrell, > >> > > >> > Thank you for your replies to my question. From Dr. Colosimo, I was > >> able > >> > to determine that the SAS results can be replicated by adding the > >> > option conf.type="log-log" to my code as in : > >> > > >> > survobj <- survfit(survfrm, conf.type="log-log", data=Survival) > >> > > >> > Originally, it looked like the SAS results could be replicated using > >> > conf.type="plain". Applying this option to my actual data revealed > that > >> > this was not the case, however. > >> > > >> >>From Dr. Harrell, I learned that using conf.type="log-log" may not be > >> such > >> a good idea. Interestingly though, I've seen at least one instance where > >> experts in the R community use this option in their book. The book is > >> about > >> 10 years old. So maybe opinion about the use of this option has shifted > >> since then. > >> > > >> > Thanks, > >> > > >> > Paul > >> > > >> > [[alternative HTML version deleted]] > >> > > >> > > >> > ______________________________________________ > >> > R-help@ 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. > >> > > >> > >> > >> ----- > >> Frank Harrell > >> Department of Biostatistics, Vanderbilt University > >> -- > >> View this message in context: > >> > http://r.789695.n4.nabble.com/Kaplan-Meier-analysis-95-CI-wider-in-R-than-in-SAS-tp4554559p4557695.html > >> Sent from the R help mailing list archive at Nabble.com. > >> > >> ______________________________________________ > >> R-help@ 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. > >> > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@ 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. > > > > > ----- > Frank Harrell > Department of Biostatistics, Vanderbilt University > -- > View this message in context: > http://r.789695.n4.nabble.com/Kaplan-Meier-analysis-95-CI-wider-in-R-than-in-SAS-tp4554559p4561432.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.
