Power calculation for Kaplan Meier Analysis

diedeaw — Thu, 05 Oct 2017 02:13:40 GMT

Hello,

Can someone tell me why I am getting the following warning?

proc power;

twosamplesurvival

curve("23")= (119 127 197 1115 1321 1391) : (0.938 0.875 0.813 0.75 0.688 0.625)

curve("411")= (56) : (0.928)

groupsurvival="23"|"411"

totaltime=4185

test=logrank

accrualtime=1

alpha=0.05

npergroup=16 14

power=.;

run ;

WARNING: The magnitude of the effect is ill-defined in 2 scenarios in the output table.

My goal is to compare 2 survival curves, one with 6 deaths (n = 16 total) and one with 1 death (n = 14 total), the total time is 4185 minutes.

SAS does do the analysis but this is my output:

Computed Power Index N per Group Power Error 1 2

16	.	Invalid input
14	.	Invalid input

I am using SAS University edition.

Thank you in advance!

Andrea

Re: Power calculation for Kaplan Meier Analysis

Norman21 — Thu, 05 Oct 2017 15:44:55 GMT

A similar questions was asked here: