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The effects of communicating uncertainty on public trust in facts and numbers.

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van der Bles, Anne Marthe  ORCID logo
van der Linden, Sander  ORCID logo
Freeman, Alexandra LJ  ORCID logo
Spiegelhalter, David J  ORCID logo


Uncertainty is inherent to our knowledge about the state of the world yet often not communicated alongside scientific facts and numbers. In the "posttruth" era where facts are increasingly contested, a common assumption is that communicating uncertainty will reduce public trust. However, a lack of systematic research makes it difficult to evaluate such claims. We conducted five experiments-including one preregistered replication with a national sample and one field experiment on the BBC News website (total n = 5,780)-to examine whether communicating epistemic uncertainty about facts across different topics (e.g., global warming, immigration), formats (verbal vs. numeric), and magnitudes (high vs. low) influences public trust. Results show that whereas people do perceive greater uncertainty when it is communicated, we observed only a small decrease in trust in numbers and trustworthiness of the source, and mostly for verbal uncertainty communication. These results could help reassure all communicators of facts and science that they can be more open and transparent about the limits of human knowledge.



communication, contested, posttruth, trust, uncertainty, Communication, Humans, Internet, Meta-Analysis as Topic, Trust, Uncertainty

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Proc Natl Acad Sci U S A

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Proceedings of the National Academy of Sciences


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Nuffield Foundation (OSP/43227)
David And Claudia Harding Foundation (unknown)
Nuffield Foundation David & Claudia Harding Charitable Foundation