Analyzing the Performance of the Classification Models in Machine Learning

Confusion matrix (also called Error matrix) is used to analyze how well the Classification Models (like Logistic Regression, Decision Tree Classifier, etc.) performs. Why do we analyze the performance of the models? Analyzing the performance of the models helps us to find and eliminate the bias and variance problem if exist and it also helps us to fine-tune the model so that the model produces more accurate results. Confusion Matrix is usually applied to Binary classification problems but can be extended to Multi-class classification problems as well. Concepts are comprehended better when illustrated with examples so let us consider an example.