arXiv Machine Learning

Sharp Bounds on the Winner's Bias under Independent and Nonnegatively Correlated Noise

arXiv Machine Learning
Jun 15

A Complexity Measure for Active Learning in Multi-group Mean Estimation

arXiv:2606. 14690v1 Announce Type: new Abstract: We study a \emph{max-risk} objective for active learning in a multi-group mean estimation $d$-armed bandits: a learner adaptively allocates a budget of $T$ samples across $d$ groups to minimize the worst-case uncertainty index $\max_{k\in[d]}\sigma_k^2/n_k$, where $\sigma_k$ is the standard deviation of the distribution of arm $d$, and $n_k$ is the number of times arm $d$ is sampled.

By Abdellah Aznag, Rachel Cummings, Adam N. Elmachtoub
arXiv Machine Learning
Sep 16

On the disintegration of the stochastic majority vote: From PAC-Bayesian bounds to a self-bounding algorithm

The paper introduces a derandomization framework for stochastic majority vote classifiers, converting PAC‑Bayesian guarantees into deterministic majority vote guarantees. By applying disintegrated PAC‑Bayesian theory to the space of vote weight vectors, the authors derive two families of high‑probability generalization bounds for both data‑independent and data‑dependent ensembles. These bounds naturally lead to a self‑bounding learning algorithm that optimizes deterministic majority vote performance.

By Julien Bastian (LabHC), Benjamin Leblanc (LabHC, UJM, MALICE), Pascal Germain (LabHC, UJM, MALICE), Amaury Habrard (LabHC, UJM, MALICE), Guillaume Metzler (ERIC), Emilie Morvant (LabHC), Paul Viallard (MALT)
arXiv Machine Learning
Sep 25

How Many Humans Are 32 LLM Judges Worth?

The paper investigates how many human annotators are equivalent to a panel of 32 large‑language‑model (LLM) judges. By comparing the panel’s label distributions to empirical human labels on three ChaosNLI tasks, the authors find two distinct effective panel sizes: distribution‑error matching yields effective sizes of 2.304, 3.750, and 3.445, while spectral matching gives 4.242, 6.459, and 6.499, indicating a 1.72–1.89× gap. The study also explores how spectral diversity, participation ratio, and panel composition affect effective size, and demonstrates that carefully chosen panels can outperform baseline accuracy while improving effective size.

By Chao Li, Yingying Yu, Yunfeng Li