---
language:
  - pl
pretty_name: Polish BookSummary
task_categories:
  - text-classification
size_categories:
  - 1K<n<10K
tags:
  - polish
  - long-context
  - document-classification
  - factual-consistency
  - literature
  - translated
  - synthetic
---

# Polish BookSummary

**Polish BookSummary** is a long-document factual-consistency classification dataset constructed from a publicly available collection of English-language book plot summaries.

Each example consists of a short **claim followed by a Polish plot summary**. The task is a **binary classification problem** in which the model must determine whether the claim is factually consistent with the information contained in the document.

Polish BookSummary is part of the **LongContext** benchmark introduced with [Polish ModernBERT](ARXIV_URL).

## Dataset statistics

| Split | Examples |
|---|---:|
| Train | 4,460 |
| Validation | 620 |
| Test | 1,248 |
| **Total** | **6,328** |

The dataset contains predominantly long inputs: **87.9%** of test examples exceed 512 tokens, **38.7%** exceed 1,024 tokens, and **8.1%** exceed 2,048 tokens when tokenized with the Polish ModernBERT Base tokenizer.

## Dataset construction

The dataset was constructed from a public collection of approximately **25.7K English-language plot summaries**. To obtain sufficiently long inputs, the **longest 25%** of the summaries were retained and translated into Polish using **GLM-4.6**.

For each summary, GLM-4.6 generated a **two- or three-sentence claim supported by the document**, with a preference for facts appearing in the second half of the summary. The claim was then prepended to the summary.

For half of the examples, the claim remains supported by the document. For the other half, the claim was modified by GLM-4.6 to make it plausible but factually inconsistent with the corresponding summary. The resulting dataset is therefore a balanced binary classification task requiring the model to verify information across a long document.

The task is evaluated using **accuracy**.

## Citation

If you use this dataset, please cite:

```bibtex
[CITATION]
```