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@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.