[R] R-Help : Warning messages using plot(cox.zph)

[Kathy-Andrée Laplante-Albert]

Hi,
 
I get a warning message when I plot cox.zph objects with the transform km and
rank, but not with id and log with the same data set. 
Here's the command:

example is a coxph object
rk <- cox.zph(example, transform='rank')
rk
 
plot(rk)
and here's the warning message:
Warning messages:
1: suppression des ex-aequos de 'x' in: approx(xx, xtime, seq(min(xx),
max(xx),
length = 17)[2 * (1:8)])
2: suppression des ex-aequos de 'x' in: approx(xtime, xx, temp)

However, no points are actually missing on my plots.

Is anybody get an idea of why this happens only with km and rank transforms
and what does this mean?

Thank you,
 
Kathy


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