Determine the area under the ROC curve for a fitted model

Evaluate the area under the ROC curve for a fitted model on new data. To be used as argument aggregation.fun in peperr call.

aggregation.auc(full.data=NULL, response, x, model, cplx=NULL,  
type=c("apparent", "noinf"), fullsample.attr = NULL, ...)

Arguments

full.data	passed from peperr, but not used for calculation.
response	vector of binary response.
x	n*p matrix of covariates.
model	model fitted as returned by a fit.fun, as used in a call to peperr.
cplx	passed from peperr, but not necessary for calculation.
type	character.
fullsample.attr	passed from peperr, but not necessary for calculation.
...	additional arguments, passed to predict function.

Details

Area under the ROC curve is calculated based on internal glmnet:::auc function from package glmnet.

Value

Scalar, indicating the area under the ROC curve.

Author

Thomas Hielscher \ t.hielscher@dkfz.de

See also

peperr

Examples

if (FALSE) {
# binomial model - classification

library(c060)
library(gridExtra)
library(ggplot2)

set.seed(0815)
x <- matrix(rnorm(100*20),100,20)
y <- sample(0:1,100,replace=TRUE)

peperr_obj <- peperr(response=y, x=x, fit.fun=fit.glmnet, args.fit=list(family="binomial"),
           complexity=complexity.glmnet, args.complexity=list(nfolds=10, family="binomial"),
           trace=F, RNG="fixed",seed=0815,
#           aggregation.fun=c060:::aggregation.misclass,                  
#           aggregation.fun=c060:::aggregation.brier,                  
           aggregation.fun=c060:::aggregation.auc,                  
           indices=resample.indices(n=nrow(x), sample.n = 100, method = "sub632"))

tmp   <- data.frame(grp="",error=unlist(peperr_obj$sample.error)) 
errs  <- data.frame(error=c(perr(peperr_obj,"resample"),
         perr(peperr_obj,"632p"),perr(peperr_obj,"app"),
         perr(peperr_obj,"nullmodel")), col  = c("red","blue","green","brown"),
         row.names=c("mean\nout-of-bag",".632plus","apparent","null model"))
                 
p     <- ggplot(tmp, aes(grp,error))
pg    <- p + geom_boxplot(outlier.colour = rgb(0,0,0,0), outlier.size=0) +
         geom_jitter(position=position_jitter(width=.1)) + 
         theme_bw() + scale_y_continuous("AUC") +  scale_x_discrete("") +
         geom_hline(aes(yintercept=error, colour=col), data=errs, show_guide=T) + 
         scale_colour_identity("error type", guide = "legend", breaks=errs$col,
         labels=rownames(errs)) +
         ggtitle("AUC \n in bootstrap samples ")                       

p2     <- ggplot(data.frame(complx=peperr_obj$sample.complexity), aes(x=complx))
pg2    <- p2 + geom_histogram(binwidth = 0.02, fill = "white", colour="black") +
          theme_bw()+  xlab(expression(lambda)) +
          ylab("frequency") + 
          geom_vline(xintercept=peperr_obj$selected.complexity, colour="red") + 
          ggtitle("Selected complexity \n in bootstrap samples") +
          ggplot2::annotate("text", x = 0.12, y = -0.5,
          label = "full data", colour="red", size=4)

grid.arrange(pg2, pg, ncol=2)

}