Hallucinations Leaderboard Eval

---
name: hallucinations-leaderboard-eval
description: This evaluation framework quantifies two distinct types of hallucinations in large language models: factuality (truthfulness of generated information) and faithfulness (consistency with input context or instructions). It probes model performance across 15 diverse knowledge-intensive tasks, including closed-book QA, summarization, reading comprehension, and fact-checking, using zero-shot and few-shot in-context prompts. Use when the user wants to benchmark on FEVER, FaithDial, NQ-open, TriviaQA, MemoTrap, TruthfulQA-MC2, XSum, or asks about evaluating this task. Reports faithfulness score, factuality score.
metadata:
  skill_kind: dataset_eval
  source_arxiv: 2404.05904
  bibtex_key: [REDACTED]
  confidence: medium
---

# hallucinations-leaderboard-eval

> The Hallucinations Leaderboard -- An Open Effort to Measure Hallucinations in Large Language Models — Hong et al. (2024) (arXiv:2404.05904, 2024)

## What this evaluates

This evaluation framework quantifies two distinct types of hallucinations in large language models: factuality (truthfulness of generated information) and faithfulness (consistency with input context or instructions). It probes model performance across 15 diverse knowledge-intensive tasks, including closed-book QA, summarization, reading comprehension, and fact-checking, using zero-shot and few-shot in-context prompts.

## Datasets

- **FEVER** — total ?; splits: test (-1)
- **FaithDial** — total ?; splits: test (-1)
- **NQ-open** — total ?; splits: test (-1)
- **TriviaQA** — total ?; splits: test (-1)
- **MemoTrap** — total ?; splits: test (-1)
- **TruthfulQA-MC2** — total ?; splits: test (-1)
- **XSum** — total ?; splits: test (-1)

## Metrics

- `faithfulness score` **(primary)** — range: percent
  - Measures the model's ability to retain fidelity to the given input context or specific instructions. Exact computation defined in Section 2.3.
- `factuality score` **(primary)** — range: percent
  - Measures the accuracy and truthfulness of the generated information against ground-truth facts. Exact computation defined in Section 2.3.

## Input / output format

**Input**: Task-specific prompts provided in zero-shot or few-shot in-context format, including questions, source documents, or instructions.

**Output**: Model-generated text or selected answer option.

## Scoring recipe

```python
for each task in evaluation_tasks:
  predictions = model.generate(prompt)
  factuality_scores[task] = compute_factuality(predictions, gold)
  faithfulness_scores[task] = compute_faithfulness(predictions, context)
aggregate_factuality = mean(factuality_scores)
aggregate_faithfulness = mean(faithfulness_scores)
return aggregate_factuality, aggregate_faithfulness
```

## Common pitfalls

- Scores are min-max normalized per task for heatmap visualization, but raw scores are reported in tables.
- Instruction fine-tuning improves faithfulness (instruction adherence) but does not consistently improve factuality, revealing a trade-off.
- Evaluation is conducted without training or fine-tuning the evaluated models.

## Evidence (verbatim from paper)

> we conducted a comprehensive analysis of the models and tasks introduced in Section [2]. In [Figure 2], we display the results of models for each task in the form of a heatmap. The value of each cell in the heatmap follows the metric of the corresponding task, and the dendrogram-shaped clusters are formed after applying min-max normalisation by task (y-axis) and model (x-axis). Table 1 shows a comparison of pre-trained models with their corresponding instruction fine-tuned variants across two metrics: faithfulness score and factuality score (Section [2.3]).

## Citation

```bibtex
@misc{hong2024hallucinationsleaderboard,
  title={The Hallucinations Leaderboard -- An Open Effort to Measure Hallucinations in Large Language Models},
  author={Hong et al. (2024)},
  year={2024},
  note={arXiv:2404.05904}
}
```

- arXiv: 2404.05904