Difference between the different measurement metric

Can someone explain what each of these mean? both in simple terms and in terms of TP, TN, FP, FN?

Also are there any other common metrics that I am missing?

  1. F-measure or F-score
  2. Recall
  3. Precision
  4. Accuracy

Topic f1score score accuracy machine-learning

Category Data Science


Lets say you are creating a model to predict whether a person has a disease or not.

True Positives (TP): Model predicts yes (they have the disease), and they do have the disease.

True Negatives (TN): Model predicts no, and they don't have the disease.

False Positives (FP): Model predicts yes, but they don't actually have the disease. (Also known as a "Type I error.")

False Negatives (FN): Model predicts no, but they actually do have the disease. (Also known as a "Type II error.")

If you look at confusion metric below enter image description here

Accuracy: Overall, how often is the classifier correct?
(TP+TN)/total = (100+50)/165 = 0.91

True Positive Rate: When it's actually yes, how often does it predict yes?
TP/actual yes = 100/105 = 0.95
also known as "Sensitivity" or "Recall"

Precision: Model predicts yes, how often is it correct?
TP/predicted yes = 100/110 = 0.91

F1 Score = 2 * (Precision * Recall)/ Precision + Recall
         =  2 * .91 * .95 / (0.91+.95) 

Other terms which people usually use are :

  1. AUC - Area Under Curve

  2. Cohen's Kappa

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