Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu


  • Tetsuya SakaiEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_80616




Q-measure is a graded-relevance version of the well-known Average Precision. Let R denote the number of known relevant documents for a topic; let gain l denote the gain value for a document of relevance level l: for example, let it be 3 for a highly relevant document, 2 for a relevant document, and 1 for a partially relevant document. For a given ranked list of documents, let I( r) = 0 if the document at rank r is nonrelevant, and I( r) = 1 otherwise; then \(C(r)=\sum _{k=1}^{r}I(k)\)
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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Waseda UniversityTokyoJapan