[R] pROC and ROCR give different values for AUC

[David Winsemius]

On Dec 19, 2012, at 4:47 AM, Ivana Cace wrote:

> Packages pROC and ROCR both calculate/approximate the Area Under (Receiver Operator) Curve. However the results are different.
> 
> I am computing a new variable as a predictor for a label. The new variable is a (non-linear) function of a set of input values, and I'm checking how different parameter settings contribute to prediction. All my settings are predictive, but some are better.
> 
> The AUC i got with pROC was much lower then expected, so i tried ROCR. Here are some comparisons:
> AUC from pROC         AUC from ROCR
> 0.49465                      0.79311
> 0.49465                      0.79349
> 0.49701                      0.79446
> 0.49701                      0.79764
> 
> When i draw the ROC (with pROC) i get the curve i expect. But why is the AUC according to pROC so different?

Why are you sending this to the Rhelp mailing list? You should instead be reporting it to the package maintainers.

> maintainer('ROCR')
[1] "Tobias Sing <tobias.sing at mpi-sb.mpg.de>"
> maintainer('pROC')
[1] "Xavier Robin <Xavier.Robin at unige.ch>"


-- 
David Winsemius
Alameda, CA, USA