Published, Version of Record (VoR) Open Access via Drexel Libraries Read and Publish Program 2026 Open CC BY V4.0
Abstract
Information systems -- Evaluation of retrieval results Information systems -- Recommender systems
Offline evaluation on historical interaction logs is the most common evaluation methodology for recommender systems. However, such evaluations depend on sparse, incomplete, or biased data, which raises concerns about whether commonly used evaluation setups reliably reflect true user preferences. In this work, we study how offline evaluation design choices affect the validity of recommender system comparisons. We evaluate a set of recommendation models across several evaluation setups that vary key factors such as data filtering thresholds and candidate set construction. To assess the validity of these configurations, we measure the correlation between model rankings obtained from conventional train–test splits on sparse interaction data and rankings from evaluations based on dense ground-truth user feedback. We use this agreement as an indication of their validity with respect to true user preferences. Our results show that the validity of sparse evaluation depends on the dataset and the specific dense evaluation targets, and that there is no uniformly best offline evaluation design.
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Details
Title
On the Convergent Validity of Offline Evaluation Designs for Recommender Systems
Creators
Sushobhan Parajuli - Drexel University
Samira Vaez Barenji - ,
Michael D. Ekstrand (Corresponding Author) - Drexel University
Contributors
Gediminas Adomavicius (Editor)
George Karypis (Editor)
Joseph A. Konstan (Editor)
Bart Goethals (Editor)
Martijn Willemsen (Editor)
Minmin Chen (Editor)
Arnab Bhadury (Editor)
Felice Antonio Merra (Editor)
Zhenhua Dong (Editor)
Publication Details
Proceedings of the 20th ACM Conference on Recommender Systems, pp 410-418
Conference
RecSys '26: 20th ACM Conference on Recommender Systems