Training and Evaluating with Human Label Variation: An Empirical Study

Kemal Kurniawan, Meladel Mistica, Timothy Baldwin, Jey Han Lau


Abstract
Human label variation (HLV) challenges the standard assumption that a labeled instance has a single ground truth, instead embracing the natural variation in human annotation to train and evaluate models. While various training methods and metrics for HLV have been proposed, it is still unclear which methods and metrics perform best in what settings. We propose new evaluation metrics for HLV leveraging fuzzy set theory. Because these new proposed metrics are differentiable, we then in turn experiment with using these metrics as training objectives. We conduct an extensive study over 6 HLV datasets testing 14 training methods and 6 evaluation metrics. We find that training on either disaggregated annotations or soft labels performs best across metrics, outperforming training using the proposed training objectives with differentiable metrics. We also show that our proposed soft micro F1 score is one of the best metrics for HLV data.1
Anthology ID:
2026.cl-1.3
Volume:
Computational Linguistics, Volume 52, Issue 1 - March 2026
Month:
March
Year:
2026
Address:
Cambridge, MA
Venue:
CL
SIG:
Publisher:
MIT Press
Note:
Pages:
85–111
Language:
URL:
https://preview.aclanthology.org/ingest-latest-mitpress-cl-tacl/2026.cl-1.3/
DOI:
10.1162/coli.a.578
Bibkey:
Cite (ACL):
Kemal Kurniawan, Meladel Mistica, Timothy Baldwin, and Jey Han Lau. 2026. Training and Evaluating with Human Label Variation: An Empirical Study. Computational Linguistics, 52(1):85–111.
Cite (Informal):
Training and Evaluating with Human Label Variation: An Empirical Study (Kurniawan et al., CL 2026)
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PDF:
https://preview.aclanthology.org/ingest-latest-mitpress-cl-tacl/2026.cl-1.3.pdf