{{technical|date=June 2018}}<!-- Needs a plain-English definition without mathematical symbols -->
The (standard) '''Boolean model''' of [[information retrieval]]''' (BIR)<ref>{{citation | author1=Lancaster, F.W. | author2=Fayen, E.G. | title=Information Retrieval On-Line | publisher=Melville Publishing Co., Los Angeles, California | year=1973}}</ref> is a classical [[information retrieval]] (IR) model and, at the same time, the first and most-adopted one. It is used by many IR systems to this day.{{citation needed|date=November 2010}} The BIR is based on [[Boolean logic]] and classical [[set theory]] in that both the documents to be searched and the user's query are conceived as sets of terms. Retrieval is based on whether or not the documents contain the query terms.
