PRISM-VLM: A Multi-Axis Discriminative Benchmark for Compact Vision-Language Models

Sanghee Park, Kee-Eung Kim


Abstract
Compact vision-language models (VLMs) now power a growing share of multimodal applications. The benchmarks used to compare them, however, inherit a frontier-centric design: each model is reduced to a single accuracy number, narrowing the inter-model gap on saturated suites and pressing models into low-score bands on harder ones. We introduce PRISM-VLM, a multi-axis discriminative benchmark that scores every item along seven axes covering the recurring failure modes (task quality, behavioral robustness, and capability bottlenecks) and combines them into a single PSCORE, with items recycled from fifteen public benchmarks. Across compact VLMs from the past two years, PSCORE separates model pairs more reliably than prior single-axis benchmarks under an item-level paired bootstrap, and surfaces behavioral differences these benchmarks average away. Even models with statistically indistinguishable PSCOREs diverge sharply along the per-axis profile, particularly on sycophancy, which is nearly orthogonal to single-prompt accuracy. We will release the full pipeline, prompts, and per-item annotations.
Anthology ID:
2026.findings-emnlp.2475
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
53259–53287
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2475/
DOI:
10.18653/2026.findings-emnlp.2475
Bibkey:
Cite (ACL):
Sanghee Park and Kee-Eung Kim. 2026. PRISM-VLM: A Multi-Axis Discriminative Benchmark for Compact Vision-Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 53259–53287, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
PRISM-VLM: A Multi-Axis Discriminative Benchmark for Compact Vision-Language Models (Park & Kim, Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.2475.pdf