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. 2011 Jun 30;17(2):120–130. doi: 10.4258/hir.2011.17.2.120

Table 4.

Comparison of different term ranking algorithms for different term reweighting methods (R = 50 and E = 15)

graphic file with name hir-17-120-i004.jpg

The mean average precision is presented for a combination of term ranking (rows) and term reweighting methods (columns), including, in parentheses, the percent (%) improvement from the unexpanded queries.

EMIM: expected mutual information measure, F4: F4MODIFIED, IDF: inverse document frequency, KLD: Knullback-Leibler divergence, LCA: local context analysis, RSV: Robertson selection value.

a(p < 0.05) and b(p < 0.01) are in bold.