Reasoning & knowledge

MMLU

by Hendrycks et al. (UC Berkeley & collaborators)

What is MMLU? MMLU is a reasoning & knowledge eval made by Hendrycks et al. (UC Berkeley & collaborators). Multiple-choice questions across 57 subjects, from elementary mathematics and US history to computer science and law, testing broad academic and professional knowledge.

Page last updated 2026-10-15 · Evals Review

Editor note

Multiple-choice questions across 57 subjects, from elementary mathematics and US history to computer science and law, testing broad academic and professional knowledge.

What it tests
World knowledge and problem solving across many school and professional subjects.
Original source
github.com/hendrycks/test
Last updated
Repo last commit 2023-04-24
License
MIT

Facts come only from the linked source (checked 15 Oct 2026). Credit belongs to the creators.

When to use MMLU

  • You want a widely reported baseline for general knowledge across 57 subjects, so you can compare with many published results.
  • You want per-subject results: the original leaderboard reports Humanities, Social Sciences, STEM and Other separately.
  • You need a harder version: MMLU-Pro adds reasoning-focused questions, raises the options from four to ten and removes trivial and noisy questions.

Limitations

  • It is multiple choice, so it measures recognition of the right answer, not free-form explanation.
  • Scores at the top have levelled off. The MMLU-Pro authors note that model performance on MMLU has begun to plateau, which makes differences hard to see, and the HLE paper reports that LLMs now score over 90%.
  • Results change with prompting: the MMLU-Pro paper measured 4–5% score sensitivity to prompt style on MMLU (about 2% on MMLU-Pro).

How to run it

  1. Download the test from the original repository (data.tar) or the Hugging Face copy (cais/mmlu).
  2. Run it in an eval harness. Stanford's HELM, for example, includes MMLU as a run entry. Report few-shot or zero-shot and the prompt format.
pip install crfm-helm
helm-run --run-entries mmlu:subject=philosophy,model=<model> --suite my-suite --max-eval-instances 10

Notable results

  • In the original paper, most models were near random chance; the largest GPT-3 model was almost 20 points above chance on average, and results were weakest on subjects such as morality and law. [Paper (arXiv)]
  • On MMLU-Pro, accuracy dropped by 16% to 33% compared with MMLU, and chain-of-thought helped more than on MMLU. [MMLU-Pro paper (arXiv)]

Sources

Everything above comes from the sources listed, read on 15 Oct 2026. Commands are copied from the official instructions; check the source for changes.

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Related reasoning & knowledge evals

  • GPQA — Expert-level science reasoning.
  • Humanity's Last Exam — Frontier academic knowledge and reasoning.
  • LiveBench — Hard, contamination-limited tasks with verifiable ground-truth answers (no LLM judge).

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