Karen Spärck Jones

Pioneer of inverse document frequency (IDF) weighting in information retrieval, Spärck Jones introduced a concept now used in most search engines today.

A British computer scientist, she was born in Huddersfield, Yorkshire, England and educated at Girton College, Cambridge. Initially she became a school teacher. She worked at Cambridge's Computer Laboratory from 1974 and retired in 2002, holding the post of Professor of Computers and Information. Spärck Jones continued to work in the Computer Laboratory until shortly before her death.

Her main research interests, from the late 1950s onward, were natural language processing and information retrieval. One of her most important contributions was the concept of inverse document frequency (IDF) weighting in information retrieval, which she introduced in a 1972 paper. IDF is used in most search engines today, usually as part of the tf-idf weighting scheme.

She was a Fellow of the British Academy, of which she was Vice-President in 2000–02. Spärck Jones was also a Fellow of both the AAAI and the ECCAI, and served as President of the Association for Computational Linguistics in 1994.

She received several awards for her research, including the Gerard Salton Award (1988), the ASIS&T Award of Merit (2002), the ACL Lifetime Achievement Award (2004), the BCS Lovelace Medal (2007), and the ACM-AAAI Allen Newell Award (2007).