Unit 7: Relevance Feedback and Query Expansion

Relevance feedback is a method that invloves IR system users refining their queries by marking returned results as relevant or irrelevant. Once this is done, the system uses the information to reformulate the query to give more accurate results. Relevance feedback helps when concepts can be referred to using different words. RF helps to differentiate word meaning to the system.

RF is ineffective when misspellings occur, documents in the collection are cross-language or when the collection vocabulary and user vocabulary are mismatched. RF also puts more demand on the user.