Jaccard Similarity

#statistics #interview

AKA Jaccard Index
AKA Jaccard Similarity Coefficient
Jaccard Similarity is used to find similarity between two binary vector or set

Binary Vector

For two binary vector, the formula is,

Jaccard Similarity = \frac{# elements where both are 1}{# elements where both are 1 + # elements where only first one is 1 + # elements where only second one is 1}

Set

For two sets $A, B$ , the formula is,

Jaccard Similarity = \frac{| A \cap B |}{| A \cup B |}

Multiset

For two Multiset $A, B$ , the formula is,

Jaccard Similarity = \frac{| A \cap B |}{| A | + | B |}

Uses:

Text Mining: To find similarity between two text documents using the term user
E-Commerce: from millions of dataset, find similar customer from their purchase history
Recommendation System: In movie recommendation system, we can use the jaccard index to find the similar users by their watch history

References

Related Notes