ROC and AUC for Model Evaluation

ROC or Receiver Operating Characteristic Curve is the most frequently used tool for evaluating the binary or multi-class classification model. Unlike other metrics, it is calculated on prediction scores like Precision-Recall Curve instead of prediction class. In my previous post, the importance of the precision-recall curve is highlighted as how to plot for multi-class classification. To understand ROC Curve, let's quickly refresh our memory on the possible outcomes in a binary classification problem by referring to the Confusion Matrix. ROC Curve is a plot of True Positive Rate(TPR) plotted against False Positive Rate(FPR) at various threshold values. It helps to visualize how threshold affects classifier performance.