arXiv Machine Learning

Selection-Safe Conformal Early Exit: Distribution-Free Coverage under Adaptive Depth

The paper introduces a selection‑safe conformal early‑exit method that calibrates a single split‑conformal quantile using a terminal‑path score derived from prefix maxima. This approach guarantees coverage for any data‑dependent stopping policy that preserves terminal‑set containment, without requiring an α/L correction. Empirical results on eight encoder backbones and CIFAR‑100 show that pathwise selection achieves higher macro coverage (0.901 vs. 0.814) with smaller set sizes and lower latency fractions compared to naive layer‑wise selection, and remains robust to deployment‑time budget changes.

arXiv Machine Learning
Oct 5

Threshold-Aware Conformal Routing

Threshold-Aware Conformal Routing (TACR) is a method that decides whether to use a fast surrogate model or a full simulator based on whether the surrogate’s conformal interval lies entirely on one side of a fixed decision threshold. TACR learns input‑dependent interval widths that are tighter near the threshold, preserving distribution‑free coverage while reducing the number of simulator calls. Experiments on scientific and engineering datasets show TACR cuts simulator deferrals by 14‑75% compared to standard conformal prediction, and by an additional 10‑24% over a variant without threshold‑aware weighting.

By Shiwei Tan, Huzefa Rangwala, Danielle C. Maddix
arXiv AI
Sep 10

Everything in Moderation: Per-Domain Coverage Optima and Alignment-Resistant Domain Gaps in Multi-Domain Mid-Training

The study investigates how the composition of data during the mid‑training phase of language models affects performance across multiple domains. Experiments with Qwen3‑8B‑Base on five distinct KOR‑Bench domains show that moderate coverage (10%‑40%) yields the best per‑domain results, and that alignment passes cannot fully close the performance gaps created by mid‑training data choices. Additionally, zero coverage in mid‑training severely degrades accuracy, while a carefully tuned allocation can provide the largest overall pipeline improvement.

By Yunpeng Xu, Kun Zheng
arXiv Machine Learning
2d ago

Does Depth Survive Composition, and Can a Router Use It? Adaptive Compute in Latent World Models

The paper investigates whether deeper predictor blocks in adaptive‑compute world models truly improve rollout accuracy and whether a router can select the appropriate depth per step. Experiments on nine DeepMind Control tasks show that deeper predictors do not always yield better accuracy, and that a greedy oracle selecting depth per step can reduce error by up to 37% compared to fixed‑depth mixtures, yet no trained router achieves this advantage. The study also finds that supervising early exits only at the first rollout step can mitigate depth‑inversion issues observed in some tasks.

By Achyuthan Sivasankar
arXiv Computation and Language
Oct 5

From Positionwise Confidence to Prefix Scheduling: Verifier Skipping in Speculative Decoding

The paper explores a new lossy strategy for speculative decoding called verifier skipping, which allows certain draft prefixes to be committed without invoking the verifier. It investigates which confidence signals—raw token confidence, learned marginal survival, or learned conditional survival—best schedule these skips, finding that raw confidence often performs best despite higher positionwise AUROC for learned signals. Experiments on HumanEval with DiffuCoder-7B-Instruct and Qwen3-32B show that all three signals can reduce verifier calls by 9.6% to 13.5% while maintaining the same pass@1 as Strict SDD.

By Haoxuan Luo, Jameson Sandler, Ferdinando Fioretto
arXiv Machine Learning
Oct 3

SimplexUQ: An Evaluation Framework and Benchmark for Conformal Uncertainty on Simplex-Valued Predictions

SimplexUQ introduces the first benchmark and reproducible protocol for evaluating how conformal prediction wrappers allocate coverage across simplex‑valued predictions. The framework, called SimplexTasks‑12, combines six synthetic regimes and six real tasks (e.g., class probabilities, topic mixtures, spectral abundances) to compare existing wrappers on metrics such as marginal coverage, worst‑stratum coverage, max disparity, and computational cost. Empirical results show that no single wrapper consistently dominates, with Mondrian and BatchMVP performing best in different settings, and that removing predictor bias only partially mitigates disparity.

By Liang You, Hengyu Shi, Dongwen Ou
arXiv Machine Learning
Sep 21

Available Guardrails: Certifying Selective Prediction across ML Systems

The paper introduces a method to certify selective prediction in machine learning systems by computing the availability of safety gates through exact-binomial inversion and dynamic programming. It demonstrates that a truth-informed planner can significantly improve mean coverage over naive approaches, and that reallocating error budgets further enhances coverage across diverse applications such as LLM tool‑calling, content moderation, lesion classification, and recommendation. The study highlights the importance of planning and finite‑sample estimation in ensuring reliable, granular deployment of selective predictors.

By Parivesh Priye, Yufeng Wang, Haibin Ling, Michael Chaykowsky
arXiv Computation and Language
Oct 7

Readout Stability in Prefill-Only Decision Models:Zero-Label Prediction and Inference-Time Compute Allocation

Prefill‑only decision models evaluate every candidate in a menu in a single forward pass, avoiding decoding and reducing cost by one to two orders of magnitude compared to generative language models. The paper demonstrates that when only the candidate menu changes, the model’s post‑intervention accuracy can be predicted solely from the cached first‑pass distribution using a simple estimator that renormalizes and selects the argmax, without any labels or second pass. Across seven model families, ten datasets, and two task types, this menu‑only intervention prediction is within 4.2 points of actual accuracy, and in one family it is exact, whereas a probability‑level variant fails by 21 points, indicating the property resides in ranking rather than calibrated probabilities.

By Ran Li, Lei Chen