velectra-base-ViFactCheck-GE

velectra-base-ViFactCheck-GE

This model is FPTAI/velectra-base-discriminator-cased fine-tuned for VFC-GE on ViFactCheck using the claim paired with gold evidence.

Evaluation protocol

• Dataset size: 7,232 examples.
• Shared fixed stratified splits for FC and GE: 5,785 train / 723 development / 724 test.
• Labels: Supported, Refuted, and Not Enough Information.
• Fine-tuning seeds: [42, 22, 202].
• Training: 3 epoch(s), AdamW, learning rate 2e-05, weight decay 0.01, warmup ratio 0.1.
• Effective train batch size: 8 (hard-validated against every published run).
• Maximum sequence length: 256.
• Input mode: raw Vietnamese claim and passage.
• The claim is always preserved; only the second sequence (gold evidence) is truncated when the pair exceeds the encoder limit.
• Topic, author, outlet, URL and other source metadata are excluded from model inputs.
• No class weighting, resampling, retrieval model, sentence ranking, test-time model selection or external evidence is used.
• Checkpoints are selected by development Macro-F1. The representative published checkpoint is seed 42, selected only by development Macro-F1.

Results

Test metrics are reported as mean ± sample standard deviation over seeds [42, 22, 202].

Per-seed results

Label mapping

{
  "0": "supported",
  "1": "refuted",
  "2": "not_enough_information"
}

Usage

import torch
from transformers import AutoModelForSequenceClassification, AutoTokenizer

model_id = "BaoNhan/velectra-base-ViFactCheck-GE"
tokenizer = AutoTokenizer.from_pretrained(model_id, use_fast=False)
model = AutoModelForSequenceClassification.from_pretrained(model_id)

claim = "Thông tin này đã được cơ quan chức năng xác nhận."
evidence = "Bài báo cung cấp bằng chứng liên quan đến phát biểu trên."
inputs = tokenizer(
    claim,
    evidence,
    return_tensors="pt",
    truncation="only_second",
    max_length=256,
)
with torch.no_grad():
    probabilities = model(**inputs).logits.softmax(dim=-1)[0]
predicted_id = int(probabilities.argmax())
print(model.config.id2label[predicted_id], probabilities.tolist())

Files

• aggregate_metrics.json: aggregate metrics and training manifest.
• artifacts/per_seed_results.csv: one row per fine-tuning seed.
• artifacts/seed_*_confusion_matrix.csv: confusion matrix for each seed.
• artifacts/seed_*_classification_report.json: per-class metrics.
• artifacts/seed_*_test_predictions.csv: IDs, gold/predicted labels and probabilities; raw claims and passages are excluded.

Limitations

ViFactCheck supplies the correct source article and therefore does not evaluate open-web evidence retrieval. VFC-FC can truncate relevant information in long articles and jointly measures verification plus robustness to irrelevant context. VFC-GE uses oracle gold evidence and must not be presented as a realistic end-to-end deployment setting. This model is a research classifier, not an automated arbiter of truth, and may produce confidently incorrect predictions.

Dataset citation

@inproceedings{hoa2025vifactcheck,
  title={ViFactCheck: A New Benchmark Dataset and Methods for Multi-domain News Fact-Checking in Vietnamese},
  author={Hoa, Tran Thai and Duy, Tran Quang and Tran, Khanh Quoc and Nguyen, Kiet Van},
  booktitle={Proceedings of the AAAI Conference on Artificial Intelligence},
  volume={39},
  number={1},
  pages={308--316},
  year={2025},
  doi={10.1609/aaai.v39i1.32008}
}