[R] Show number at risk on Kaplan Meier curve

[Mark Wardle]

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

-- 
Specialist Registrar and Clinical Research Fellow,
Department of Neurology, Cardiff University, UK