On the Rejection Criterion for Proxy-based Test-time Alignment

Fuente: arXiv
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Hauptverfasser: Hammal, Ayoub, Zweigenbaum, Pierre, Corro, Caio
Format: Preprint
Veröffentlicht: 2026
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author Hammal, Ayoub
Zweigenbaum, Pierre
Corro, Caio
author_facet Hammal, Ayoub
Zweigenbaum, Pierre
Corro, Caio
contents Recent works proposed test-time alignment methods that rely on a small aligned model as a proxy that guides the generation of a larger base (unaligned) model. The implicit reward approach skews the large model distribution, whereas the nudging approach defers the generation of the next token to the small aligned model when the large base one is unconfident about its outcome. In this work, we first show that both approaches can be reduced to sampling from similar graphical models, where they differ only in the definition of a rejection criterion (or distribution). Moreover, we argue that the confidence criterion is ill-motivated due to linguistic phenomena like ambiguous phrasing. We propose a novel rejection criterion based on a conservative confidence bet. Experimentally, our novel approach outperforms previous work on several datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16146
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On the Rejection Criterion for Proxy-based Test-time Alignment
Hammal, Ayoub
Zweigenbaum, Pierre
Corro, Caio
Computation and Language
Recent works proposed test-time alignment methods that rely on a small aligned model as a proxy that guides the generation of a larger base (unaligned) model. The implicit reward approach skews the large model distribution, whereas the nudging approach defers the generation of the next token to the small aligned model when the large base one is unconfident about its outcome. In this work, we first show that both approaches can be reduced to sampling from similar graphical models, where they differ only in the definition of a rejection criterion (or distribution). Moreover, we argue that the confidence criterion is ill-motivated due to linguistic phenomena like ambiguous phrasing. We propose a novel rejection criterion based on a conservative confidence bet. Experimentally, our novel approach outperforms previous work on several datasets.
title On the Rejection Criterion for Proxy-based Test-time Alignment
topic Computation and Language
url https://arxiv.org/abs/2604.16146