Extended Boolean model

<p>The Extended Boolean model was described in a Communications of the ACM article appearing in 1983, by Gerard Salton, Edward A. Fox, and Harry Wu. The goal of the Extended Boolean model is to overcome the drawbacks of the Boolean model that has been used in <a href="/facts/Information_retrieval/MFSmpeNw">information retrieval</a>. The Boolean model doesn't consider term weights in queries, and the result set of a Boolean query is often either too small or too big. The idea of the extended model is to make use of partial matching and term weights as in the vector space model. It combines the characteristics of the <a href="/facts/Vector_Space_Model/WC1LqLA5">Vector Space Model</a> with the properties of <a href="/facts/Boolean_algebra_(logic)/VkCToAmg">Boolean algebra</a> and ranks the similarity between queries and documents. This way a document may be somewhat relevant if it matches some of the queried terms and will be returned as a result, whereas in the <a href="/facts/Standard_Boolean_model/EjHXxx9y">Standard Boolean model</a> it wasn't.
</p><p>Thus, the extended Boolean model can be considered as a generalization of both the Boolean and vector space models; those two are special cases if suitable settings and definitions are employed. Further, research has shown effectiveness improves relative to that for Boolean query processing.  Other research has shown that <a href="/facts/Relevance_feedback/bDYwe063">relevance feedback</a> and <a href="/facts/Query_expansion/poSUBUTD">query expansion</a> can be integrated with extended Boolean query processing.
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Extended Boolean model open-in-new

Extended Boolean model