PHEB: An European Portuguese High School-Level LLM Benchmark

Diogo C. Tavares, Rafael Ferreira, Afonso Simplício, Gonçalo Vinagre, Ana Carolina Condez, Inês Calvo, Inês Vieira, David Semedo, Joao Magalhaes


Abstract
We present PHEB, a comprehensive benchmark designed to evaluate Large Language Models (LLMs) on real high school level national exams in European Portuguese. The goal is to promote the development of NLP tools and provide a reliable resource for benchmarking multilingual and educational capabilities of LLMs. Covering over 3,500 questions spanning 18 years (2006–2023) across six core subjects, the benchmark compiles high-quality questions from Portuguese National Exams, written and thoroughly curated by professors to ensure topic diversity, linguistic accuracy, and alignment with national curricula. PHEB spans a wide range of subjects, including Mathematics, Portuguese Language and Literature, History, Geography, Biology/Geology, and Philosophy. Questions incorporate both multiple-choice and long-form answers to assess factual knowledge, reasoning capabilities, and language understanding. We comprehensively benchmark state-of-the-art LLMs, shedding light on key challenges such as models’ knowledge, language coverage, answer format biases and robustness to machine translation.
Anthology ID:
2026.lrec-1.367
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
4673–4683
Language:
External URL:
https://lrec.elra.info/lrec2026-main-367
DOI:
10.63317/2o3fvueefvwj
Bibkey:
Cite (ACL):
Diogo C. Tavares, Rafael Ferreira, Afonso Simplício, Gonçalo Vinagre, Ana Carolina Condez, Inês Calvo, Inês Vieira, David Semedo, and Joao Magalhaes. 2026. PHEB: An European Portuguese High School-Level LLM Benchmark. In Proceedings of the Fifteenth Language Resources and Evaluation Conference, pages 4673–4683, Palma de Mallorca, Spain. ELRA Language Resource Association.
Cite (Informal):
PHEB: An European Portuguese High School-Level LLM Benchmark (Tavares et al., LREC 2026)
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