Improving retrieval feedback with multiple term-ranking function combination

Claudio Carpineto, Giovanni Romano, Vittorio Giannini
2002 ACM Transactions on Information Systems  
and VITTORIO GIANNINI WIND Telecomunicazioni S.p.A ________________________________________________________________________ In this paper we consider methods for automatic query expansion from top retrieved documents (i.e., retrieval feedback) which make use of various functions for scoring expansion terms within Rocchio's classical reweighting scheme. An analytical comparison shows that the retrieval performance of methods based on distinct term-scoring functions is comparable on the whole
more » ... le on the whole query set but considerably differs on single queries, consistent with the fact that the ordered sets of expansion terms suggested for each query by the different functions are largely uncorrelated. Motivated by these findings, we argue that the results of multiple functions can be merged, by analogy with ensembling classifiers, and present a simple combination technique based on the rank values of the suggested terms. The combined retrieval feedback method is effective not only with respect to unexpanded queries but also to any individual method, with notable improvements on the system's precision. Furthermore, the combined method is robust with respect to variation of experimental parameters and it is beneficial even when the same information needs are expressed with shorter queries.
doi:10.1145/568727.568728 fatcat:5ptoxedt5nhh7lwv4hux7w7qdy