vzani/portuguese-fake-news-classifier-logreg-tfidf-combined

Logistic Regression (TF-IDF) for Fake News Detection (Portuguese)

Model Overview

This repository contains Logistic Regression classifiers trained on TF-IDF features for fake news detection in Portuguese. The model is trained and evaluated on corpora derived from Brazilian Portuguese datasets Fake.br and FakeTrue.Br.

• Architecture: Logistic Regression (scikit-learn)
• Features: TF-IDF over unigrams/bigrams/trigrams
• Task: Binary text classification (Fake vs. True)
• Language: Portuguese (pt)
• Framework: scikit-learn
• Training source code: https://github.com/viniciuszani/portuguese-fake-new-classifiers

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Available Variants

• logreg-tfidf-combined Fine-tuned using the combined dataset from Fake.br and FakeTrue.Br.

• logreg-tfidf-fake-br Fine-tuned using the Fake.br dataset from Fake.br.

• logreg-tfidf-faketrue-br Fine-tuned using the FakeTrue.Br dataset from FakeTrue.Br.

Each variant has its own confusion matrix, classification report, and predictions stored as artifacts.

---

Training Details

{
    "ngram_upper": 3,
    "min_df": 4,
    "max_df": 0.89364813327021,
    "C": 276.8531184839476,
    "solver": "saga",
}

---

Evaluation Results

Evaluation metrics are stored in the repo as:

• confusion_matrix.png
• final_classification_report.parquet
• final_predictions.parquet

These files provide per-class performance and prediction logs for reproducibility.

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How to Use

This model is stored as final_model.joblib.

import joblib
from huggingface_hub import hf_hub_download

repo_id = "vzani/portuguese-fake-news-classifier-logreg-tfidf-combined"  # or fake-br / faketrue-br
filename = "final_model.joblib"

model_path = hf_hub_download(repo_id=repo_id, filename=filename)
clf = joblib.load(model_path)


def predict(text: str) -> tuple[bool, float]:
    prob = clf.predict_proba([text])[0][1]
    pred = prob >= 0.5

    # Convert the probability in case of Fake
    prob = prob if pred else 1 - prob
    return bool(pred), float(prob)


if __name__ == "__main__":
    text = "BOMBA! A Dilma vai taxar ainda mais os pobres!"
    print(predict(text))

The expected output is a Tuple where the first entry represents the classification (True for true news and False for fake news) and the second the probability assigned to the predicted class (ranging from 0 to 1.0).

(False, 0.9997890870088925)

Source code

You can find the source code that produced this model in the repository below:

• https://github.com/viniciuszani/portuguese-fake-new-classifiers

The source contains all the steps from data collection, evaluation, hyperparameter fine tuning, final model tuning and publishing to HuggingFace. If you use it, please remember to credit the author and/or cite the work.

License

• Base model BERTimbau: Apache 2.0
• Fine-tuned models and corpora: Released under the same license for academic and research use.

Citation

@misc{zani2025portuguesefakenews,
  author       = {ZANI, Vinícius Augusto Tagliatti},
  title        = {Avaliação comparativa de técnicas de processamento de linguagem natural para a detecção de notícias falsas em Português},
  year         = {2025},
  pages        = {61},
  address      = {São Carlos},
  school       = {Instituto de Ciências Matemáticas e de Computação, Universidade de São Paulo},
  type         = {Trabalho de Conclusão de Curso (MBA em Inteligência Artificial e Big Data)},
  note         = {Orientador: Prof. Dr. Ivandre Paraboni}
}