An initial query is usually a wild guess. Retrieved query results are then used to help construct a more precise query or modify the database indexes. Choose important terms, or expressions, attached to certain previously retrieved documents that have been identified as relevant by the users, and of enhancing the importance of these terms in a new query formulation.
Methods
- Reweight the query terms based on the distribution of these terms in the relevant and irrelevant documents retrieved in response to the queries.
- Query modification, which could be implicit or explicit, is based on changing the actual terms in the query.
- Automatic query expansion helps users formulate their queries.
- Relevance feedback allows users to give feedback by choosing from a list of words or documents to clarify the ambiguity in a query.
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A Query Expansion Example
Adjust the initial query in an attempt to avoid unrelated or less-related query results; e.g., the modified query Q1 could use the formula on the right.
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