- Paul Ogilvie, Jamie Callan. 2001. The effectiveness of query expansion for distributed information retrieval. Abstract: Query expansion has been shown effective for both single database retrieval and for distributed information retrieval where complete collection information is available. One might expect that query expansion would then work for distributed information retrieval when complete collection information is not available. However, this does not appear to be the case. When using local context analysis for query expansion in distributed retrieval with partial information, the most significant reason query expansion does not work is that merging scores of documents retrieved by expanded queries is very difficult. However, we have found that using sampled information for query expansion can give boosts in a single database environment, and that when more information is available, query expansion can work in distributed environments. We also show that most of the benefit of query expansion in distributed retrieval comes from finding good documents, and not from selecting good databases.
