Online Learning-to-Defer with Varying Experts

arXiv:2605.12340 · stat.ML, cs.LG · Submitted 2026-05-12 · Read on arXiv

stat.ML, cs.LG

Submitted: 2026-05-12

Updated: 2026-08-28

License: http://creativecommons.org/licenses/by/4.0/

The gist: Learning-to-Defer (L2D) methods route each query either to a predictive model or to external experts.

Terminology

Abstract

Learning-to-Defer (L2D) methods route each query either to a predictive model or to external experts. Real-world deployments require handling streaming data, changing expert availability, shifting expert reliability, and feedback observed only for the selected action. We introduce an online multiclass L2D algorithm that combines queried-action bandit feedback with a dynamically varying pool of experts. Let N=n+n e, let B bound the Frobenius norm of the linear score matrix, and let ρ bound the augmented input norm. Assuming linear calibration and zero surrogate minimizability gap for the projected comparator class, our method achieves expected true-deferral regret O((BN 3/2ρ+1)T 2/3), improving to O(BN 3/2ρ sqrt T+B 2N 3ρ 2) under a concentrated-score condition. The analysis combines an online H-consistency transfer bound with projected online convex optimization. Experiments on synthetic and real-world datasets demonstrate selective routing under varying expert availability and reliability.

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