https://communities.sas.com/t5/Statistical-Procedures/CONFTYPE-LOGLOG-or-LINEAR-in-PROC-LIFETEST/m-p/799784#M39343 Linear limits can sometimes go outside the interval (0,1). The CONFTYPE=loglog generally gives better coverage than linear limits and has been the default for a long time. It is not related to sample size.<BR /> Thu, 03 Mar 2022 09:18:45 GMT OsoGris 2022-03-03T09:18:45Z https://communities.sas.com/t5/Statistical-Procedures/CONFTYPE-LOGLOG-or-LINEAR-in-PROC-LIFETEST/m-p/799700#M39339 <P>Hi, I am using PROC LIFETEST to generate the KM curve and its confidence band. I noticed that there is an option called CONFTYPE= (default is LOGLOG) which can let us choose the type of transformation to calculate the confidence band. I also tried CONFTYPE=LINEAR, and the confidence band is different. To me, the results from LINEAR makes more sense, but I am not sure if I can use it.&nbsp;<SPAN>My question is, is there any rule to choose the type of transformation? Is it related to the sample size?&nbsp;</SPAN></P> Wed, 02 Mar 2022 22:02:53 GMT https://communities.sas.com/t5/Statistical-Procedures/CONFTYPE-LOGLOG-or-LINEAR-in-PROC-LIFETEST/m-p/799700#M39339 Chaupak 2022-03-02T22:02:53Z https://communities.sas.com/t5/Statistical-Procedures/CONFTYPE-LOGLOG-or-LINEAR-in-PROC-LIFETEST/m-p/799784#M39343 Linear limits can sometimes go outside the interval (0,1). The CONFTYPE=loglog generally gives better coverage than linear limits and has been the default for a long time. It is not related to sample size.<BR /> Thu, 03 Mar 2022 09:18:45 GMT https://communities.sas.com/t5/Statistical-Procedures/CONFTYPE-LOGLOG-or-LINEAR-in-PROC-LIFETEST/m-p/799784#M39343 OsoGris 2022-03-03T09:18:45Z