Neighborhood Evaluation in Recommender Systems Using the Realization Based Entropy Approach

Roee Anuar*, Yossi Bukchin, Oded Maimon, Lior Rokach

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The task of a recommender system evaluation has often been addressed in the literature, however there exists no consensus regarding the best metrics to assess its performance. This research deals with collaborative filtering recommendation systems, and proposes a new approach for evaluating the quality of neighbor selection. It theorizes that good recommendations emerge from good selection of neighbors. Hence, measuring the quality of the neighborhood may be used to predict the recommendation success. Since user neighborhoods in recommender systems are often sparse and differ in their rating range, this paper designs a novel measure to asses a neighborhood quality. First it builds the realization based entropy (RBE), which presents the classical entropy measure from a different angle. Next it modifies the RBE and propose the realization based distance entropy (RBDE), which considers also continuous data. Using the RBDE, it finally develops the consent entropy, which takes into account the absence of rating data. The paper compares the proposed approach with common approaches from the literature, using several recommendation evaluation metrics. It presents offline experiments using the Netflix database. The experimental results confirm that consent entropy performs better than commonly used metrics, particularly with high sparsity neighborhoods. This research is supported by The Israel Science Foundation, Grant #1362/10. This research is supported by NHECD EC, Grant #218639.

Original languageEnglish
Pages (from-to)34-50
Number of pages17
JournalInternational Journal of Business Analytics
Issue number4
StatePublished - 1 Oct 2014


FundersFunder number
NHECD EC218639
Israel Science Foundation1362/10


    • Collaborative Filtering
    • Entropy
    • Information Systems
    • Information Theory
    • Recommender Systems


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