plot.cox.zph {survival} R Documentation

## Graphical Test of Proportional Hazards

### Description

Displays a graph of the scaled Schoenfeld residuals, along with a smooth curve.

### Usage

## S3 method for class 'cox.zph'
plot(x, resid=TRUE, se=TRUE, df=4, nsmo=40, var,
xlab="Time", ylab, lty=1:2, col=1, lwd=1, hr=FALSE, ...)


### Arguments

 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 to use for the lines 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 This has been superseded by a subscripting method; see the example below. hr if TRUE, label the y-axis using the estimated hazard ratio rather than the estimated coefficient. (The plot does not change, only the axis label.) xlab label for the x-axis of the plot ylab optional label for the y-axis of the plot. If missing a default label is provided. This can be a vector of labels. lty, col, lwd line type, color, and line width for the overlaid curve. Each of these can be vector of length 2, in which case the second element is used for the confidence interval. ... additional graphical arguments passed to the plot function.

### Side Effects

a plot is produced on the current graphics device.

coxph, cox.zph.

### Examples

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


[Package survival version 3.5-5 Index]