Karen Ida Boalth Spärck Jones FBA (26 August 1935 – 4 April 2007) was a self-taught programmer and a pioneering British computer scientist responsible for the concept of inverse document frequency (IDF), a technology that underlies most modern search engines.

[7]" In 2019, The New York Times published her belated obituary in its series Overlooked,[8][9] calling her "a pioneer of computer science for work combining statistics and linguistics, and an advocate for women in the field.

[16] Spärck Jones was educated at a grammar school in Huddersfield and then from 1953 to 1956 at Girton College, Cambridge, studying history, with an additional final year in Moral Sciences (philosophy).

[9] While working at the CLRU, Spärck Jones began pursuing her Ph.D. At the time of submission, her Ph.D thesis was cast aside as uninspired and lacking original thought, but was later published in its entirety as a book.

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.