The Madrigal Database manages and serves archival and real-time data from upper-atmosphere science instruments in multiple formats.
vectara/hallucination-leaderboard
"leaderboard Comparing LLM Performance at Producing Hallucinations when Summarizing Short Documents".

About vectara/hallucination-leaderboard
The vectara/hallucination-leaderboard is an open-source GitHub repository that hosts a public leaderboard ranking large language models (LLMs) by their rate of hallucination when summarizing short documents. It uses Vectara's Hallucination Evaluation Model (HHEM) to generate standardized, comparable metrics for each tested model, with planned regular updates as both the evaluation tool and the set of evaluated LLMs are updated over time.
The leaderboard reports four core metrics for every listed model: hallucination rate, factual consistency rate, answer rate, and average summary length in words. An interactive version of the leaderboard is hosted on Hugging Face, and archived versions of previous leaderboard iterations are available for users who want to reference older data. The repository includes supporting files including a citation guide, open-source license, and README for users seeking to access or reuse the dataset.
Key features
- Ranks LLMs by hallucination rate when summarizing short documents
- Uses Vectara's HHEM for standardized hallucination evaluation
- Tracks hallucination rate, factual consistency, answer rate, and summary length per model
- Interactive version hosted on Hugging Face for easier browsing
- Archived previous leaderboard versions available for reference
- Open-source repository with citation guide and license included
- Open-source and freely accessible to all users
- Uses a standardized evaluation model for consistent cross-model comparisons
- Includes multiple relevant performance metrics per tested LLM
- Planned regular updates to reflect new models and evaluation improvements
- Only evaluates LLM performance on short-document summarization tasks, not other use cases
- Results are tied to Vectara's proprietary HHEM evaluation methodology
vectara/hallucination-leaderboard at a glance
- Category
- Research & Data › Open Data & Datasets
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Open source
- Yes · Source code
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
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vectara/hallucination-leaderboard FAQ
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