arXiv Machine Learning

Calibration Count Reuse: Validity Does Not Determine Efficiency

arXiv AI
Oct 16

Rethinking Calibration for High-Sparsity LLM Pruning: From Single Sources to Capability Coverage

The paper argues that post‑training pruning of large language models should use a calibration set that covers multiple capability domains rather than a single source. A balanced four‑way mixture of sources consistently outperforms any single source across sparsity levels, model scales, and held‑out benchmarks. When aligned corpora are unavailable, the IGSP method approximates this mixture using only the base model and an evaluation taxonomy, achieving significant gains over prior self‑generation approaches.

By Hu Xu, Zhaolong Xing, Congcong Liu, Jiaxing Wang, Zhida Jiang, Junshi Huang, Zhen Chen, Jianfeng Xu
arXiv Machine Learning
Sep 29

Missingness-Aware Conformal Prediction Under Cross-Hospital Distribution Shift

The paper introduces a missingness‑aware conformal calibration method for mortality prediction that accounts for cross‑hospital distribution shifts. By selecting a measurement on an independent sample, grouping patients by whether that measurement is recorded, and applying Mondrian calibration within each group, the method avoids reusing calibration outcomes. Experiments on eICU and MIMIC‑IV data show that, compared to pooled calibration, it reduces the worst‑group coverage gap by a median of 1.9 percentage points across six settings, though the benefit varies with predictor and hospital.

By Liang You, Dongwen Ou, Hengyu Shi, Siyuan Dai
arXiv Machine Learning
Sep 23

Density-Ratio Rescoring for Imbalanced Classification Using Raking Duals and Classifier Scores

Density‑Ratio Rescoring (DRR) enhances a classifier trained with the original class prior by adding a survey‑raking dual score that reweights the majority class to match minority feature moments within a tolerance. The method standardizes both the dual and base scores, combines them with equal weight, and uses the fitted dual directly for prediction without resampling or refitting the base model. Experiments on 24 tabular benchmarks and a gene‑expression cohort show that DRR improves average precision over the standardized base on every dataset, with a mean gain of 0.034, and outperforms a shared‑dual raking‑and‑relabeling resampler on most datasets.

By Dongha Kim, Seunghwan Park
arXiv Machine Learning
Sep 24

When Accuracy Gaps Fail to Certify: Auditing Cross-Domain Recalibration of LLM Judges

The study examines whether accuracy gaps between source and target tasks can certify the failure of scalar recalibration maps for large language model judges. Across thirteen judges, two generators, eight domains, and 1,176 transfers, the accuracy gap only provides a weak lower bound on target calibration error and can predict opposite outcomes. Even with a finite‑sample lower certificate, the method shows low power (0.13) and does not reliably indicate when recalibration will fail.

By Fariya Afrin, Ibne Farabi Shihab