Agentic data science with the Data Agent Kit
cloud.google.com·8h ago
AI Research
arXiv CS.AI·Aug 7·5 min read
The em-dash em-beds in Congress: A population-level rise in em-dash frequency in U.S. congressional press releases at the dawn of the large-language-model era, 2021-2025
TL;DR
A significant increase in the use of unspaced em-dashes in U.S. congressional press releases was observed from 2021 to 2025, likely influenced by large language models. The frequency of these dashes more than doubled in 2025 compared to earlier years, indicating a shift in writing style.
✦ Why It Matters
Consider reviewing your writing style to align with emerging trends influenced by AI tools.
Key Takeaways
- Monitor changes in writing styles influenced by AI tools.
- Analyze your organization's press releases for stylistic trends.
- Consider adopting new punctuation styles to enhance readability.
- Stay informed about the impact of LLMs on professional writing.
Full Summary
This study investigates the stylistic impact of large language models (LLMs) on U.S. congressional press releases, focusing on the em-dash (U+2014). Traditionally, U.S. press writing follows AP style, which prefers spaced dashes.
Analyzing 146,239 press releases from 480 congressional offices between 2021 and 2025, researchers measured the density of unspaced em-dashes per 1,000 characters. Results showed a stable density of 0.10-0.12 from 2021 to 2024, followed by a rise to 0.217 in 2025, with the proportion of releases using unspaced em-dashes increasing from approximately 13% to 24.8%.
This trend was consistent across offices and survived various falsification tests, suggesting a broad adoption of LLM-assisted writing. However, the study notes that while the em-dash serves as a population-level marker, it does not definitively indicate authorship.