Reading Time in the Wild: An Assessment of Readability Predictors Based on Naturally-Observed Reading Times
Summary
Readability research often uses reading time as a proxy for text difficulty, but most of that evidence comes from lab studies with eye-tracking or self-paced reading. This paper asks whether those findings hold for unsupervised, everyday online reading. Through a partnership with the Mediahuis publishing group, the authors obtained clickstream data for Dutch news articles published in 2024. They converted aggregated reading time into average seconds per token and removed duplicates, skimmed articles and paywalled items, which left 2,929 regional articles. Candidate predictors were grouped into four dimensions: text profiling (Profiling-UD, T-Scan), readability metrics (LiNT, Flesch-Douma, Brouwer Index), LLM surprisal, and article metadata. Each was tested for correlation with per-token reading time and for predictive power. None of the proxies correlated meaningfully with reading time, and none supported reliable prediction. The authors also used an LLM to simplify the texts to CEFR B1. Unexpectedly, the models then predicted longer per-token reading times. The authors conclude that clickstream reading time should be treated cautiously as a signal of readability or comprehension.
Key points
- Data and filtering: The raw data covered 24,946 Mediahuis articles from 2024. Articles were kept only if they had at least 100 words, at least 25 views and a reading time of at least 0.15 s per token. This left 2,929 articles from Mediahuis Noord.
- Feature dimensions:
- Text profiling: Profiling-UD and T-Scan.
- Readability metrics: LiNT, Flesch-Douma and Brouwer Index.
- LLM surprisal: tweety-7b-dutch-v24a, Qwen3-4B, fietje-2 and mGPT.
- Metadata: topic, newspaper and day of week.
- Contrast with existing corpora: Unlike the controlled eye-tracking corpora RaCCooNS, MECO and GECO, this dataset reflects uncontrolled reading behaviour averaged over thousands of readers.
- Simplification effects: B1-level LLM simplification lowered many syntactic measures, such as dependency lengths and relative clauses. However, it raised surprisal scores in most texts (mean relative change of about +0.5 to +0.6), and predicted reading time per token went up.
- Availability: Code is published on GitHub (sijbrenvv/Reading-time-in-the-wild). The dataset is available only on request, under a license and a non-disclosure agreement.
Cite
@inproceedings{vaals2026reading,
title = {{Reading Time in the Wild: An Assessment of Readability Predictors Based on Naturally-Observed Reading Times}},
author = {Vaals, Sijbren van and Noord, Rik van and Nissim, Malvina},
booktitle = {Proceedings of the Fifteenth Language Resources and Evaluation Conference},
year = {2026},
doi = {10.63317/56xa82ywv9us},
url = {https://doi.org/10.63317/56xa82ywv9us}
}References
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