What is the F1 Score?

What is the F1 Score?



The F1 measure is the harmonic mean, or weighted average, of the precision and recall scores. Also called the f-measure or the f-score, the F1 score is calculated using the following formula:

F1 = 2(PR/(P + R))


The F1 measure penalizes classifiers with imbalanced precision and recall scores, like the trivial classifier that always predicts the positive class. A model with perfect precision and recall scores will achieve an F1 score of one.


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