Show number at risk on Kaplan Meier curve
Mark Wardle wrote:
Dear all, I'm using the "survival" package with R 2.4.0 on Mac OS X 10.4.8. I have two core statistics books (one of which is Altman's medical stats book) which suggest showing the number of individuals at risk at different time intervals on the Kaplan-Meier curve. My plot shows two curves that later cross, because of one significant outlier. I have two queries: Is there an easy way of displaying number of individuals at risk at a specific time interval? Is there a way to stop plotting when the number of individuals at risk reaches a certain minimum threshold to reduce the risk of such an outlier problem? If there is no easy solution, then I suppose I shall have to perform the logic myself, calculating when individuals "drop out", and overlaying that onto the plot? Many thanks, Mark
library(Design) # which also requires the Hmisc package f <- cph( ..., surv=TRUE) survplot(f, ..., n.risk=TRUE) ?survplot for details
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University