Discriminative Power And Retrieval Effectiveness Of Phrasal Indexing Terms
نویسنده
چکیده
In spite of long controversy, effectiveness of phrasal indexing is not yet clear. Recently, correlation between query length and effect of phrasal indexing is reported. In this paper, terms extracted from the topic set of the NACSIS test collection 1 are analyzed utilizing statistic tools in order to show distribution characteristics of single word/phrasal terms with regard to relevant/nonrelevant documents. Phrasal terms are found to be very good discriminators in general but not all of them are effective as supplemental phrasal terms. A distinction of informative / neutral / destructive phrasal terms is introduced. Retrieval effectiveness is examined utilizing query weight ratio of these three categories of phrasal terms.
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