Slide 37: Receiver operating characteristic analysis (ROC)
A second method of assessing model accuracy is receiver operating characteristic analysis (ROC). This compares the sensitivity of a model (the true positive fraction, or extent to which is correctly predicts species presence) and the specificity (the true negative fraction). These factors are plotted against each other for a range of different thresholds, and the area under the curve is then calculated. Once again, the assessment value is between 0 and 1, with values over 0.8 being good, and those below 0.6 being a poor fit.