Create a tolerance plot
Description
Create a tolerance plot according to the methods of Henderson, Jones & Stare (2001)
Usage
1  toleranceplot(formula, data, coverage = 0.8, horizon, plot = TRUE, xlab)

Arguments
formula 
Formula for prediction model to be used as in

data 
Data set in which to interpret the formula 
coverage 
The coverage for the tolerance intervals (default is 0.8) 
horizon 
The horizon, maximum value to be imputed in case of censored observations; default is 1.05 times largest event time 
plot 
Should the tolerance plot actually be plotted? Default is

xlab 
Label for xaxis 
Details
Warnings will be issued each time the survival curve corresponding to a value of x never goes below (1coverage)/2; these warnings may be ignored.
Value
A data frame with columns
x 
Predictor (centered at zero) 
lower 
Lower bound of tolerance interval 
upper 
Upper bound of tolerance interval 
and with attributes "coverage"
and
"horizon"
(copied from input or default).
Author(s)
Hein Putter H.Putter@lumc.nl
References
Henderson R, Jones M & Stare J (2001), Accuracy of point predictions in survival analysis, Statistics in Medicine 20, 30833096.
van Houwelingen HC, Putter H (2012). Dynamic Prediction in Clinical Survival Analysis. Chapman & Hall.
Examples
1 2  data(ova)
toleranceplot(Surv(tyears, d) ~ Karn + Broders + FIGO + Ascites + Diam, data = ova)
