Evaluation Framework for Highlight Explanations of Context Utilisation in Language Models

Fuente: arXiv
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Main Authors: Sun, Jingyi, Atanasova, Pepa, Choudhury, Sagnik Ray, Islam, Sekh Mainul, Augenstein, Isabelle
Format: Preprint
Published: 2025
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author Sun, Jingyi
Atanasova, Pepa
Choudhury, Sagnik Ray
Islam, Sekh Mainul
Augenstein, Isabelle
author_facet Sun, Jingyi
Atanasova, Pepa
Choudhury, Sagnik Ray
Islam, Sekh Mainul
Augenstein, Isabelle
contents Context utilisation, the ability of Language Models (LMs) to incorporate relevant information from the provided context when generating responses, remains largely opaque to users, who cannot determine whether models draw from parametric memory or provided context, nor identify which specific context pieces inform the response. Highlight explanations (HEs) offer a natural solution as they can point the exact context pieces and tokens that influenced model outputs. However, no existing work evaluates their effectiveness in accurately explaining context utilisation. We address this gap by introducing the first gold standard HE evaluation framework for context attribution, using controlled test cases with known ground-truth context usage, which avoids the limitations of existing indirect proxy evaluations. To demonstrate the framework's broad applicability, we evaluate four HE methods -- three established techniques and MechLight, a mechanistic interpretability approach we adapt for this task -- across four context scenarios, four datasets, and five LMs. Overall, we find that MechLight performs best across all context scenarios. However, all methods struggle with longer contexts and exhibit positional biases, pointing to fundamental challenges in explanation accuracy that require new approaches to deliver reliable context utilisation explanations at scale.
format Preprint
id arxiv_https___arxiv_org_abs_2510_02629
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evaluation Framework for Highlight Explanations of Context Utilisation in Language Models
Sun, Jingyi
Atanasova, Pepa
Choudhury, Sagnik Ray
Islam, Sekh Mainul
Augenstein, Isabelle
Computation and Language
Context utilisation, the ability of Language Models (LMs) to incorporate relevant information from the provided context when generating responses, remains largely opaque to users, who cannot determine whether models draw from parametric memory or provided context, nor identify which specific context pieces inform the response. Highlight explanations (HEs) offer a natural solution as they can point the exact context pieces and tokens that influenced model outputs. However, no existing work evaluates their effectiveness in accurately explaining context utilisation. We address this gap by introducing the first gold standard HE evaluation framework for context attribution, using controlled test cases with known ground-truth context usage, which avoids the limitations of existing indirect proxy evaluations. To demonstrate the framework's broad applicability, we evaluate four HE methods -- three established techniques and MechLight, a mechanistic interpretability approach we adapt for this task -- across four context scenarios, four datasets, and five LMs. Overall, we find that MechLight performs best across all context scenarios. However, all methods struggle with longer contexts and exhibit positional biases, pointing to fundamental challenges in explanation accuracy that require new approaches to deliver reliable context utilisation explanations at scale.
title Evaluation Framework for Highlight Explanations of Context Utilisation in Language Models
topic Computation and Language
url https://arxiv.org/abs/2510.02629