🏆 GermEval 2025 Harmful Content Detection Model Zoo

Interactive testing interface for all 6 submitted models
Detecting harmful content in German social media

Author: Samuel Ruairí Bullard (@abullardUR) | University of Regensburg



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🎯 Task Overview

The GermEval 2025 Shared Task focuses on detecting harmful content in German social media. The provided datasets primarily originate from the public German-language Twitter network of a right‑wing extremist group. Our submission addresses three subtasks:

📢 Subtask 1: Call to Action (C2A)

  • Binary detection of so‑called call to actions, i.e. calls for risky actions (e.g. criminal offences, demonstrations with possible escalation potential)

🏛️ Subtask 2: Attacks on Democratic Basic Order (DBO)

  • Fine‑grained classification into four forms of statements and (violent) attacks against the free and democratic basic order of the Federal Republic of Germany (Nothing, Criticism, Agitation, Subversive)

⚔️ Subtask 3: Violence Detection (VIO)

  • Binary detection of disturbing, violence‑related statements in tweets

📊 Performance Summary

Task Class-Weighted CW + Focal Loss
C2A 0.82 0.82
DBO 0.63 0.56
VIO 0.82 0.81

Macro-F1 scores on competitions hidden test set. Bold indicates best approach per task.

🛠️ Model Architecture

  • Base: LSX-UniWue/ModernGBERT_134M
  • Task Heads: Binary/Multi-class classification layers
  • Optimization: Bayesian hyperparameter search via Weights & Biases Sweeps

📈 Training Strategy

  • Data Split: 80% train / 20% validation (stratified)
  • Class Imbalance Handling:
    • Inverse frequency class weights
    • Focal Loss with optimized γ parameter
  • Evaluation: Macro-F1 score (primary metric)