Insights into the area under the receiver operating characteristic curve (AUC) as a discrimination measure in species distribution modeling

Jiménez Valverde, A., 2012. Insights into the area under the receiver operating characteristic curve (AUC) as a discrimination measure in species distribution modelling. Global Ecology and Biogeography, 21(4), pp.498–507. http://doi.wiley.com/10.1111/j.1466-8238.2011.00683.x

The AUC has been popularized as an omnipotent statistic in assessing the predictive accuracy of species distribution models. Most studies rationalize using the AUC value as a means to rank models by claiming that it avoids setting arbitrary thresholds for predictive decisions. Here, this claim is examined in relation to the relatedness between the AUC and sensitivity/specificity for modeling realized and potential niches. By definition, the AUC should not depend on any particular point on the ROC curve but in both simulated and real data there was a strong relationship between AUC values and certain points (the point closest to perfect detection and the point where specificity=sensitivity) on the ROC curve. In different settings (ie. studying the realized vs. potential niche), the fact that the AUC depends on certain points could be problematic because weighting errors should not be the same in each circumstance. For instance, type 1 errors (false positives) should not count as much as false negatives in modeling potential distributions as they do in modeling realized distributions. Thus, the author suggests that instead of reporting AUC values only, reporting contingency tables with varying thresholds for sensitivity and specificity may actually give us more insight into the predictability of SDMs. Overall, I agree with the author that researchers evaluating model performance need to be aware of the problems associated with using AUC values, but I am unsure of a systematic approach that would be appropriate to reporting contingency tables with thresholded values of sensitivity and specificity.