plot.coxr {coxrobust}

Plot Diagnostics for a coxr Object

Description

Graphical tool which in a series of 5 graphs let us compare how well data are explained by the estimated proportional hazards model with non-robust (black color) and robust method (green color). The first graph gives standardized difference of two estimated survival functions; one via the Cox model and the other via Kaplan Meier estimator. The following four graphs show the same differences for four strata, defined by the quartiles of the estimated linear predictor. Comparison of estimation results along with analysis of the graphs leads frequently to a very detailed information about the model fit (see examples).

Usage

## S3 method for class 'coxr'
plot(
  x,
  caption = c("Full data set", "First quartile", "Second quartile", "Third quartile",
    "Fourth quartile"),
  main = NULL,
  xlab = "log time",
  ylab = "standardized survival differences",
  ...,
  color = TRUE
)

Arguments

x

coxr object, typically result of coxr.

caption

captions to appear above the plots.

main

overall title for the plot.

xlab

title for the x axis.

ylab

title for the y axis.

...

other parameters to be passed through to plotting functions.

color

if FALSE grayscale mode is used.

Value

Data frame containing the following variables:

• timevector of survival times.

• statusvector of censoring status.

• X1, X2, ...explanatory variables (their number is determined by the dimension of vector of regression coefficients).