A Survey of Automatic Query Expansion in Information Retrieval

Abstract-The relative ineffectiveness of information retrieval systems is largely caused by the inaccuracy with which a query formed by a few keywords models the actual user information need. One well known method to overcome this limitation is automatic query expansion (AQE), whereby the user’s original query is augmented by
new features with a similar meaning. AQE has a long history in the information retrieval community but it
is only in the last years that it has reached a level of scientific and experimental maturity, especially in laboratory settings such as TREC. This survey presents a unified view of a large number of recent approaches to
AQE that leverage various data sources and employ very different principles and techniques. The following
questions are addressed. Why is query expansion so important to improve search effectiveness? What are
the main steps involved in the design and implementation of an AQE component? What approaches to AQE
are available and how do they compare? Which issues must still be resolved before AQE becomes a standard
component of large operational information retrieval systems (e.g., search engines)?