Confusion Matrix Metric

What is a Confusion Matrix?

A Confusion Matrix is a table that summarizes the performance of a classification model by showing the counts of correct and incorrect predictions for each class.

Structure (Binary Classification)

Predicted Positive Predicted Negative
Actual Positive True Positive (TP) False Negative (FN)
Actual Negative False Positive (FP) True Negative (TN)

Derived Metrics

  • Accuracy = (TP + TN) / Total
  • Precision = TP / (TP + FP)
  • Recall = TP / (TP + FN)
  • Specificity = TN / (TN + FP)

How to Read

  • Diagonal: Correct predictions
  • Off-diagonal: Errors
  • Row sums: Actual class totals
  • Column sums: Predicted class totals

Related Terms

  • Accuracy: Proportion correct
  • Precision: Positive predictive value
  • Recall: Sensitivity