In computer science, and particularly in search engines, relevance is a numerical score assigned to a search result, representing how well the result meets the information need of the user that issued the search query. In many cases, a result’s relevance determines the order in which it is presented to the user.
In academic information retrieval, the word relevance has been used in system evaluation for over forty years, going back to the Cranfield Experiments of the early 1960s. In the relatively new commercial search realm, among web search engine companies, search engine optimizers, and in the press, the incorrect relevancy is mistakenly being used more and more instead of the correct relevance. One can often tell from which community an information retrieval practitioner hails, depending on whether he or she uses the correct form of the word. Wikipedia’s search facility is an example of use of the incorrect relevancy.