What is an F1 Score?

//What is an F1 Score?
What is an F1 Score? 2017-10-04T20:00:55+00:00

Definition: F1 score is defined as the harmonic mean between precision and recall. It is used as a statistical measure to rate performance. In other words, an F1-score (from 0 to 9, 0 being lowest and 9 being the highest) is a mean of an individual’s performance, based on two factors i.e. precision and recall.

What Does F1 Score Mean?

What is the definition of F1 score? Precision is defined as the accuracy of judgment. For example, in a random population sample of 100 people, to be counted for composition of male and female, Person A estimates the count of male population to be 70. If actually, the male count is 70 in the lot, Person A is said to have a 100% precision. Essentially, it is the ratio of estimates converting into reality.


Recall is identifying all the units in a sample that testify to a certain attribute. In the above example, if we know that actually there is a 7:3 Male to Female ratio, and person A is able to estimate only 56 out of the 70 male in the sample, the recall ration comes down to 84%. Recall is the ability to identify the number of samples that would really count positive for a specific attribute.

In the field of statistics, to ascribe a simple number that would easily define the precision and recall scores of a test or an individual, a number ranging from 0 to 9 is assigned to depict the accuracy. This number is the harmonic mean of the score percentages of a test on each, precision and recall.

Summary Definition

Define F1 Score: An F1-score means a statistical measure of the accuracy of a test or an individual. It is composed of two primary attributes, viz. precision and recall, both calculated as percentages and combined as harmonic mean to assign a single number, easy for comprehension.