**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.

## Example

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.