Qwen3-8B-UnBias-Plus-SFT

A fine-tuned version of Qwen3-8B for news media bias detection and neutral rewriting, developed by the Vector Institute as part of the UnBias-Plus project.

Given a news article, the model identifies biased language segments, classifies their bias type and severity, provides neutral replacements, and returns a fully rewritten unbiased version of the article — all in a single structured JSON response.

Model Details

Property	Value
Base model	Qwen/Qwen3-8B
Fine-tuning method	Supervised Fine-Tuning (SFT) with LoRA
Training precision	bf16 (full precision, no quantization during training)
LoRA rank	16
Training framework	Unsloth + TRL
Context length	8192 tokens
Output format	Structured JSON

Usage

from unsloth import FastLanguageModel
import torch, json

model, tokenizer = FastLanguageModel.from_pretrained(
    "vector-institute/Qwen3-8B-UnBias-Plus-SFT",
    max_seq_length=8192,
    load_in_4bit=False,   # set True for ~5GB VRAM (laptop)
    dtype=torch.bfloat16,
)
FastLanguageModel.for_inference(model)

SYSTEM_PROMPT = """You are an expert linguist and bias detection specialist.
Your task is to carefully read a news article, detect ALL biased language,
and return a structured JSON response. Return ONLY valid JSON, no extra text."""

article = "Your news article here..."

messages = [
    {"role": "system", "content": SYSTEM_PROMPT},
    {"role": "user", "content": f"Analyze the following article for bias and return the result in the required JSON format.\n\nARTICLE:\n{article}"},
]

inputs = tokenizer.apply_chat_template(
    messages,
    tokenize=True,
    add_generation_prompt=True,
    enable_thinking=True,
    return_tensors="pt",
    return_dict=True,
)

outputs = model.generate(
    input_ids=inputs["input_ids"].to("cuda"),
    attention_mask=inputs["attention_mask"].to("cuda"),
    max_new_tokens=4096,
    temperature=0.1,
    do_sample=True,
    pad_token_id=tokenizer.eos_token_id,
)

new_tokens = outputs[0][inputs["input_ids"].shape[1]:]
response = tokenizer.decode(new_tokens, skip_special_tokens=True)

# Extract JSON — strip thinking block if present
if "</think>" in response:
    response = response.split("</think>", 1)[-1].strip()

result = json.loads(response)

Output Schema

{
  "binary_label": "biased" | "unbiased",
  "severity": 0 | 2 | 3 | 4,
  "bias_found": true | false,
  "biased_segments": [
    {
      "original": "exact substring from input article",
      "replacement": "neutral alternative phrase",
      "severity": "high" | "medium" | "low",
      "bias_type": "loaded language | dehumanizing framing | false generalizations | framing bias | euphemism/dysphemism | politically charged terminology | sensationalism",
      "reasoning": "1-2 sentence explanation"
    }
  ],
  "unbiased_text": "Full rewritten neutral article"
}

Severity Scale

Value	Meaning
0	Neutral — no bias detected
2	Recurring biased framing
3	Strong persuasive tone
4	Inflammatory rhetoric

Bias Types Detected

Loaded language — words with strong emotional connotations
Dehumanizing framing — language that strips dignity from groups
False generalizations — sweeping statements ("they always", "all of them")
Framing bias — selective wording that implies a viewpoint
Euphemism/dysphemism — softening or hardening language to manipulate perception
Politically charged terminology — labels used to provoke rather than describe
Sensationalism — exaggerated language to evoke emotional responses

Training Data

Fine-tuned on vector-institute/Unbias-plus, a curated dataset of news articles with expert-annotated bias labels, segment-level annotations, and neutral rewrites.

Hardware Requirements

Setup	Configuration
Recommended (server)	`load_in_4bit=False, dtype=torch.bfloat16` (~16GB VRAM)
Lightweight (laptop)	`load_in_4bit=True` (~5GB VRAM)

Choosing Between 4B and 8B

	4B	8B
VRAM (bf16)	~8GB	~16GB
VRAM (4-bit)	~3GB	~5GB
Speed	Faster	Slower
Quality	Strong	Higher accuracy on complex articles
Recommended for	Laptops, real-time APIs	Servers, batch processing

Limitations

Trained primarily on English-language news articles
Political bias detection reflects patterns in the training data
Best performance on articles under 5000 characters
As with all language models, outputs should be reviewed by a human before use in production

Citation

If you use this model in your research or application, please cite:

@misc{unbias-plus-8b,
  title        = {Qwen3-8B-UnBias-Plus-SFT},
  author       = {Vector Institute},
  year         = {2026},
  publisher    = {HuggingFace},
  howpublished = {\url{https://huggingface.co/vector-institute/Qwen3-8B-UnBias-Plus-SFT}},
  note         = {Part of the UnBias-Plus project: https://github.com/VectorInstitute/unbias-plus}
}