Skip to main content
. Author manuscript; available in PMC: 2009 Sep 21.
Published in final edited form as: Inf Retr Boston. 2009;12(1):69–80. doi: 10.1007/s10791-008-9074-8

Table 5.

Results of the 2006 and 2007 TREC topics with and without query expansion as measured by mean rank precision. Retrieved documents are sorted in reverse chronological order.

TREC Query Expansion P@5 P@10 P@20
2006 Yes 0.556 0.540 0.540
No 0.523 0.517 0.524
2007 Yes 0.385 0.411 0.413
No 0.434 0.454 0.452