# pROC 1.3 released

I just released the version 1.3 of pROC.

This function introduces several bug fixes and speed improvements, along with some new features. You can detect if two ROC curves are paired:

library(pROC) data(aSAH) rocs100 <- roc(aSAH$outcome, aSAH$s100) rocwfns <- roc(aSAH$outcome, aSAH$wfns) are.paired(rocs100, rocwfns)

A new method for the `roc.test`

is also introduced: the Venkatraman's test^{1}. Unlike bootstrap and DeLong^{2} methods, it doesn't assess the equality of the AUC. Instead, it looks at the shape of ROC curves. Two ROC curves with the same AUC but a different shape will be significantly different

set.seed(1) response <- round(runif(1000, 0, 1)) predictor1 <- response + rnorm(1000) predictor2 <- response + rlnorm(1000) roc1 <- roc(response, predictor1, plot=TRUE) roc2 <- roc(response, predictor2, plot=TRUE, add=TRUE) roc.test(roc1, roc2) roc.test(roc1, roc2, method="venkatraman", boot.n=200)

I generate two artificial ROC curves. Their AUC is not different, and the DeLong test gives a non significant result. However their shapes are highly dissimilar, and the Venkatraman's test finds a significant difference.

Here is the full change log:

- CI is not re-computed by default in
`smooth.roc`

. You can still turn it on with`reuse.ci=TRUE`

. - New function
`are.paired`

. - Local maximas could be incorrectly detected in
`coords`

(and`plot.roc`

) with`predictor`

s containing more than 2 levels. - New method
`venkatraman`

for`roc.test`

. - MASS and tcltk packages are now only suggested instead of required (R only).
`...`

not passed correctly in`plot.ci.se`

with`type="bars"`

resulting in an error (R only).

As usual, you can find the new version on ExPASy and on the CRAN. To update, type `update.packages()`

or `install.packages("pROC")`

if you want to update pROC only.

- 1. E. S. Venkatraman and Colin B. Begg (1996) “A distribution-free procedure for comparing receiver operating characteristic curves from a paired experiment”.
*Biometrika***83**, 835–848. DOI: 10.1093/biomet/83.4.835. - 2. Elisabeth R. DeLong, David M. DeLong and Daniel L. Clarke-Pearson (1988) “Comparing the areas under two or more correlated receiver operating characteristic curves: a nonparametric approach”.
*Biometrics***44**, 837–845.

Xavier Robin

Published Friday, August 13, 2010 18:35 CEST

Permalink: /blog/2010/08/13/proc-1.3-released

Tags:
pROC

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