Stephen Robertson (computer scientist)

Stephen Robertson is a British computer scientist. He is known for his work on information retrieval and the Okapi BM25 weighting model.
After completing his undergraduate degree in mathematics at Cambridge University, he took an MS at City University, and then worked for ASLIB. He then studied for his PhD at University College London under the renowned statistician and scholar B. C. Brookes. He then returned to City University working there from 1978 until 1998 in the Department of Information Science, continuing as a part-time professor and subsequently as professor emeritus. He is also a fellow of Girton College, Cambridge University.
From 1998 to 2013 he worked in the Cambridge laboratory of Microsoft Research, where he led a group investigating core search processes such as term weighting, document scoring and ranking algorithms, combining evidence from different sources, and metrics and methods for the evaluation and optimisation of search. Much of his work has contributed to the Microsoft search engine Bing. He participated a number of times in the TREC conference.