From Open Risk Manual
The c-statistic, also known as AUROC (area under the curve), the concordance statistic, is equal to to the AUC (area under curve)
- The closer the value is to 1, the better the model's classification performance
- A value of 0.5 indicates that the model is no better than classifying outcomes randomly
- A value below 0.5 means that using the opposite of the model classification is actually a better choice!