Encyclopedia of Database Systems

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


  • Ethan ZhangEmail author
  • Yi ZhangEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_483


Harmonic mean of recall and precision


Assume an information retrieval (IR) system has recall R and precision P on a test document collection and an information need. The F-measure of the system is defined as the weighted harmonic mean of its precision and recall, that is, \( F=\frac{1}{\alpha \frac{1}{P}+\left(1-\alpha \right)\frac{1}{R}} \)

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.University of CaliforniaSanta CruzUSA
  2. 2.Yahoo! Inc.Santa ClaraUSA

Section editors and affiliations

  • Weiyi Meng
    • 1
  1. 1.Dept. of Computer ScienceState University of New York at BinghamtonBinghamtonUSA