Saved in:
Bibliographic Details
Main Authors: Bohacek, Maty, Scherrer, Nino, Dufour, Nicholas, Leung, Thomas, Bregler, Christoph, Chan, Stephanie C. Y.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2512.20638
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866916067246342144
author Bohacek, Maty
Scherrer, Nino
Dufour, Nicholas
Leung, Thomas
Bregler, Christoph
Chan, Stephanie C. Y.
author_facet Bohacek, Maty
Scherrer, Nino
Dufour, Nicholas
Leung, Thomas
Bregler, Christoph
Chan, Stephanie C. Y.
contents The evaluation of large language models relies heavily on standardized benchmarks. These benchmarks provide useful aggregated metrics, but can obscure (i) particular sub-areas where the models are weak ("model gaps") and (ii) imbalanced coverage in the benchmarks themselves ("benchmark gaps"). To automatically uncover both types of gaps, we propose a simple new method using concept activations from sparse autoencoders, to identify fine-grained gaps on a per-concept basis. The method also benefits from grounding evaluation in the model's internal representations, as well as easy comparison across benchmarks. We applied the method to five popular open-source models and more than a dozen benchmarks, as illustrative examples. As validation of the approach, we found that our automatic, unsupervised method was able to recover model gaps that have been previously documented in the literature (e.g. relating to sycophancy), in addition to identifying novel model gaps. We were also able to automatically uncover benchmark gaps: core concepts that should fall within the scope of a given benchmark. Our "competency gaps" method can be used to complement existing benchmarks, by providing a concept-level decomposition of model behavior, and by helping benchmark developers iterate upon benchmark design. Code is available at https://competency-gaps.github.io.
format Preprint
id arxiv_https___arxiv_org_abs_2512_20638
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Uncovering Competency Gaps in Large Language Models and Their Benchmarks
Bohacek, Maty
Scherrer, Nino
Dufour, Nicholas
Leung, Thomas
Bregler, Christoph
Chan, Stephanie C. Y.
Computation and Language
Artificial Intelligence
Machine Learning
The evaluation of large language models relies heavily on standardized benchmarks. These benchmarks provide useful aggregated metrics, but can obscure (i) particular sub-areas where the models are weak ("model gaps") and (ii) imbalanced coverage in the benchmarks themselves ("benchmark gaps"). To automatically uncover both types of gaps, we propose a simple new method using concept activations from sparse autoencoders, to identify fine-grained gaps on a per-concept basis. The method also benefits from grounding evaluation in the model's internal representations, as well as easy comparison across benchmarks. We applied the method to five popular open-source models and more than a dozen benchmarks, as illustrative examples. As validation of the approach, we found that our automatic, unsupervised method was able to recover model gaps that have been previously documented in the literature (e.g. relating to sycophancy), in addition to identifying novel model gaps. We were also able to automatically uncover benchmark gaps: core concepts that should fall within the scope of a given benchmark. Our "competency gaps" method can be used to complement existing benchmarks, by providing a concept-level decomposition of model behavior, and by helping benchmark developers iterate upon benchmark design. Code is available at https://competency-gaps.github.io.
title Uncovering Competency Gaps in Large Language Models and Their Benchmarks
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2512.20638