# Study Finds Prompt Formatting Alone Can Flip LLM Leaderboard Rankings

Under a token-controlled protocol, wrappers that differ only in formatting shift model scores enough to reorder benchmarks, and the authors propose a Format Sensitivity Index to measure it.

- Published: 2026-07-15T05:45:50.502Z
- Canonical: https://polylog.news/ai/2026-07-15/study-finds-prompt-formatting-alone-can-flip-llm-leaderboard
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [arXiv](https://arxiv.org/abs/2607.09665)

A paper on the Format Sensitivity Index documents a problem that undermines confidence in public leaderboards. Prompt wrappers that differ only in formatting, not in content, can change a model's score enough to reverse the ranking conclusi…

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