arXiv Machine Learning

Neyman Orthogonal Activation Steering

The paper introduces a new framework for activation steering in large language models, distinguishing between the steering direction (estimand) and the method used to recover it (estimator). It shows that most existing techniques can be viewed as plug‑in estimators of the average gradient of an outcome regression, and proposes a complementary estimator based on the Stein score to directly target the gradient. By combining these approaches, the authors achieve an orthogonalized estimator with double‑robustness properties and demonstrate its effectiveness on benchmark datasets.

arXiv AI
Oct 12

Revisiting Tabular Deep Regression: Objectives and the Limits of Global Early Stopping

The paper systematically evaluates regression objectives for tabular deep learning across many datasets and neural backbones, finding that most alternatives to Mean Squared Error (MSE) offer limited or inconsistent gains, while quantile loss consistently improves performance. It identifies a limitation of global early stopping: different noise levels in target regions reach optimal performance at different epochs, causing a compromise. To address this, the authors propose a heteroskedasticity‑aware extension of quantile loss using input‑dependent label smoothing, which outperforms standard quantile loss on several backbones.

By Danil Rudenko, Georgii Bulgakov, Nikolay Kartashev, Ivan Rubachev, Daniil Krasylnikov, Artem Babenko
arXiv AI
Sep 30

OTROPE: Optimal Transport-based Robust Off-policy Evaluation for Large Language Models

The paper introduces OTROPE, a likelihood‑free method for off‑policy evaluation of large language models (LLMs) that uses optimal transport to align labeled samples from a behavior model with unlabeled samples from a target model in a semantic space. OTROPE corrects human‑labeled residuals with proxy predictors, achieving a doubly robust evaluation without requiring behavior‑policy modeling or density‑ratio estimation. The authors provide theoretical guarantees for consistency and convergence, and demonstrate through synthetic and real LLM tasks that OTROPE outperforms existing baselines and can elevate weaker evaluators to match or exceed stronger ones.

By Liner Xiang, Wenbo Zhang, Hengrui Cai
arXiv AI
Aug 20

From Inference to Adaptation: A Unified Optimal Transport View of Vision Language Model

arXiv:2608. 18339v1 Announce Type: cross Abstract: Vision-language models (VLMs) have demonstrated remarkable zero-shot capabilities yet remain sensitive to real-world distribution shifts during inference.

By Qi Yu, Zhichen Zeng, Katherine Tieu, Xiyuan Yang, Ruizhong Qiu, Yuchen Yan, Lihui Liu, Yanjun Zhao, Lingjie Chen, Jingrui He, Hanghang Tong
arXiv Machine Learning
Jul 10

Prediction-Powered Active Testing

arXiv:2607. 08347v1 Announce Type: cross Abstract: Active testing provides a label--efficient approach to risk estimation by adaptively selecting which test points should be labelled.

By Kianoosh Ashouritaklimi, Valentin Kilian, Daolang Huang, Tom Rainforth, Fran\c{c}ois Caron
arXiv AI
Sep 10

Deep Barycentric Regression for Optimal Transport Map Estimation and its Statistical Optimality

The paper introduces BROT, a two‑step approach for estimating optimal transport maps. First, it computes the unregularized OT plan, then fits a deep neural network to the resulting barycentric targets using least‑squares regression. The authors prove that, under standard regularity conditions, BROT achieves the minimax convergence rate when the true OT map is Lipschitz, and demonstrate its effectiveness on synthetic data, images, and downstream tasks such as single‑cell perturbation prediction and unsupervised domain adaptation.

By Kunwoong Kim, Insung Kong, Yongdai Kim
arXiv AI
Oct 15

Constraint-Aware Influence Estimation in Deep Constrained Learning

The paper introduces the Directional Influence Function (DIF), a new estimator for measuring how training samples affect the solution of constrained learning problems. DIF incorporates constraints directly by formulating optimality conditions as a variational inequality, thereby avoiding the bias seen in classical influence functions. Experiments on constrained linear regression and fairness‑constrained CNNs show that DIF accurately predicts changes in test loss and aligns closely with actual retraining results.

By Xin Wang (Jeff), R. Tyrrell Rockafellar (Jeff), Xuegang (Jeff), Ban