plot.cox.zph {survival}  R Documentation 
Displays a graph of the scaled Schoenfeld residuals, along with a smooth curve.
## S3 method for class 'cox.zph': plot(x, resid=TRUE, se=TRUE, df=4, nsmo=40, var, ...)
x 
result of the cox.zph function.

resid 
a logical value, if TRUE the residuals are included on the plot, as well as the smooth fit.

se 
a logical value, if TRUE , confidence bands at two standard errors
will be added.

df 
the degrees of freedom for the fitted natural spline, df=2 leads
to a linear fit.

nsmo 
number of points used to plot the fitted spline. 
var 
the set of variables for which plots are desired. By default, plots are
produced in turn for each variable of a model. Selection of a single variable
allows other features to be added to the plot, e.g., a horizontal line at
zero or a main title.
This has been superseded by a subscripting method; see the example below. 
... 
additional arguments passed to the plot function.

a plot is produced on the current graphics device.
vfit < coxph(Surv(time,status) ~ trt + factor(celltype) + karno + age, data=veteran, x=TRUE) temp < cox.zph(vfit) plot(temp, var=5) # Look at Karnofsy score, old way of doing plot plot(temp[5]) # New way with subscripting abline(0, 0, lty=3) # Add the linear fit as well abline(lm(temp$y[,5] ~ temp$x)$coefficients, lty=4, col=3) title(main="VA Lung Study")