SemEval 2026, Task 10: Span Extraction & Conspiracy Classification2026
Multi-role semantic span extraction and document-level conspiracy classification and prediction
Subtask 1: Span-based Multi-Role Information Extraction
- Built a RoBERTa-large encoder with pooled span representations from boundary, width, and contextual features.
- Designed role-specific IoU thresholds for Action, Effect, and Evidence and implemented a custom decoding pipeline with containment-based NMS and span merging.
- Tuned decision thresholds on held-out validation data.
- Achieved 0.23 decoded micro-F1 under IoU-based span matching.
Subtask 2: Document-level Conspiracy Classification
- Trained a RoBERTa-large 3-class classifier (Yes / No / Can't tell) with stratified train–validation split, label smoothing, and early stopping.
- Ran multi-seed training and selected the best checkpoint by weighted F1.
- Reached 0.77 weighted F1 on validation.
