TF.IDF (term frequency – inverse document frequency) is a numerical statistic that indicates how important a word or phrase is to a document within a collection of documents.
It is a score that is proportional to the number of times a word appears in the document offset by the frequency of the word in the collection of documents.
It’s calculated by multiplying the “term frequency” of the word appearing in the document and the “inverse document frequency” of the word across all documents.
It’s designed to measure how relevant a term is to a particular document compared to other documents in the set.
In people-oriented searches like job postings, TF.IDF can help identify words related to certain positions or roles, so employers can accurately compare resumes with job qualifications.
(See also BM25)