PoliSpace: Political Opinion Prediction using Shared Latent Space

Johanna D’Ciofalo Khodaverdian, Frédéric Berdoz, Roger Wattenhofer


Abstract
Modeling and predicting political opinions remains a challenging task for AI systems. We introduce PoliSpace, a framework that embeds individuals and political questions into a shared latent space, where vector alignment directly reflects agreement. Individuals are represented as learnable vectors, and questions are encoded via a contrastively fine-tuned language model with individual-specific affine transformations to capture subjective interpretation. This design yields an embedding space that is robust to question rephrasing and sensitive to negation. Evaluated on real-world voting data from Swiss national elections, PoliSpace achieves an 89.81% F1 score on seen opinion prediction for rephrased questions, outperforming prior embedding-based approaches (66.17% F1). We further introduce retrieval and confidence-aware thresholding mechanisms that reach up to 100% F1 at reduced coverage, demonstrating how the learned embedding space can be leveraged to improve prediction reliability. Ablation studies confirm the importance of both individual-specific interpretation modeling and negation-aware encoder fine-tuning. The learned individual embedding space also exhibits clear clustering by political party affiliation, despite no party-label supervision during training, capturing the underlying ideological structure of the Swiss political landscape.
Anthology ID:
2026.aacl-long.243
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
5447–5463
Language:
URL:
https://aclanthology.org/2026.aacl-long.243/
DOI:
Bibkey:
Cite (ACL):
Johanna D’Ciofalo Khodaverdian, Frédéric Berdoz, and Roger Wattenhofer. 2026. PoliSpace: Political Opinion Prediction using Shared Latent Space. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 5447–5463, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
PoliSpace: Political Opinion Prediction using Shared Latent Space (Khodaverdian et al., AACL-IJCNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.aacl-long.243.pdf