- Should you need an excellent reference book about KM, I used and cited (cit below) a book by Klein & Moeschberger. There are certainly other excellent texts. You can refer to the original Kaplan Meier paper and they refer to the Greenwood calculation.

I wrote a paper which does not -directly- answer your question but -might- help. We discovered that there was a difference in how SAS vs other packages (R, SPLUS , etc.) computed the mean of the Kaplan meier. In our application (in health economics) the impact on the estimation was substantial

http://www.barkerstats.com/PDFs/tas.pdf I reference the KM confidence intervals settings in the software for SPLUS, SAS, R, in the paper.

I don't have a SAS manual and I'll assume you mean you're getting these from the ODS output. And there might be a "switch" to turn on to get the quantities you're interested in. SAS manual should have excellent documentation about the calculation.

And SAS has confidence limits and confidence regions/bands.

------------------------------

Chris Barker, Ph.D.

2022 Statistical Consulting Section

Chair-elect

Consultant and

Adjunct Associate Professor of Biostatistics

www.barkerstats.com---

"In composition you have all the time you want to decide what to say in 15 seconds, in improvisation you have 15 seconds."

-Steve Lacy

------------------------------

Original Message:

Sent: 12-23-2022 09:37

From: Nancy Buderer

Subject: kaplan meier confidence intervals for failure

I'm seeking advice on how to get the confidence limits for kaplan meier failure times out of SAS? I'm using proc lifetest for a simple kaplan meier. The outsurv option gives for each time point the probability of survival, probability of failure, standard error of survival and the confidence limits for survival.

Since failure is just 1 - survival, would it be acceptable to use 1 - confidence limit for survival as my confidence limits for failure?

Or, can I use failure +- 1.96(standard error of survival)?

Any input is greatly appreciated.

nancybuderer@gmail.com

------------------------------

Nancy Buderer, MS

Nancy Buderer Consulting, LLC

Biostatistician, Program Evaluator, Research Consultant

------------------------------