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Posts Talk Policy, Stories Don’t: Policy-Issue Detection on Instagram with Fine-Tuned Transformers and Prompted LLMs
Achmann-Denkler, Michael
, Haim, Mario and Wolff, Christian
(2026)
Posts Talk Policy, Stories Don’t: Policy-Issue Detection on Instagram with Fine-Tuned Transformers and Prompted LLMs.
In: The 3rd Workshop on Natural Language Processing for Political Sciences (PoliticalNLP 2026), Co-located with LREC 2026 — 11–16 May 2026, Palma de Mallorca, Spain.
Date of publication of this fulltext: 20 May 2026 07:40
Conference or workshop item
DOI to cite this document: 10.5283/epub.79454
Abstract
Policy issues are central to election campaigns, yet systematic analyses of issue communication on Instagram remain scarce—particularly for ephemeral Stories. We develop and evaluate automated methods for detecting the binary presence of policy issues in Instagram posts and Stories from the 2021 German federal election. Drawing on a gold-standard dataset of 1,357 annotated documents across three ...
Policy issues are central to election campaigns, yet systematic analyses of issue communication on Instagram remain scarce—particularly for ephemeral Stories. We develop and evaluate automated methods for detecting the binary presence of policy issues in Instagram posts and Stories from the 2021 German federal election. Drawing on a gold-standard dataset of 1,357 annotated documents across three textual channels (captions, OCR-extracted image text, and speech transcripts), we compare a fine-tuned German transformer (GBERT) with multiple LLM prompting strategies (zero-shot, few-shot, retrieval-augmented). Both approaches prove effective: GBERT achieves a cross-validated macro F1 of 0.90, closely matched by GPT-o3 under few-shot prompting (0.88). Substantively, policy visibility varies far more by content format than by party: 70% of posts contain policy references compared to only 17% of Stories, a pattern that holds consistently across all eight parties. An exploratory topic model confirms that parties reproduce familiar issue-ownership profiles within the subset of policy-relevant texts. Our results establish binary issue detection as a feasible foundation for studying policy communication in multimodal, ephemeral social media environments.
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Details
| Item type | Conference or workshop item (Paper) |
| ISBN | 978-2-493814-76-0 |
| Title of Book: | The 3rd Workshop on Natural Language Processing for Political Sciences (PoliticalNLP 2026) @ LREC 2026 |
|---|---|
| Publisher: | European Language Resources Association (ELRA) |
| Open Access Type: | CC-License |
| Place of Publication: | Palma de Mallorca |
| Page Range: | pp. 120-130 |
| Date | 16 May 2026 |
| Institutions | Languages and Literatures > Institut für Information und Medien, Sprache und Kultur (I:IMSK) > Lehrstuhl für Medieninformatik (Prof. Dr. Christian Wolff) Informatics and Data Science > Department Human-Centered Computing > Lehrstuhl für Medieninformatik (Prof. Dr. Christian Wolff) |
| Keywords | policy issues, Instagram, political communication, text classification, LLMs, German federal election |
| Dewey Decimal Classification | 000 Computer science, information & general works > 004 Computer science |
| Status | Published |
| Refereed | Yes, this version has been refereed |
| Created at the University of Regensburg | Partially |
| URN of the UB Regensburg | urn:nbn:de:bvb:355-epub-794545 |
| Item ID | 79454 |
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