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When unlikely outcomes occur: the role of communication format in maintaining communicator credibility

Jenkins, Sarah C.; Harris, Adam J.L.; Lark, Murray


Sarah C. Jenkins

Adam J.L. Harris

Professor of Geoinformatics


The public expects science to reduce or eliminate uncertainty (Kinzig & Starrett, 2003), yet scientific forecasts are probabilistic (at best) and it is simply not possible to make predictions with certainty. Whilst an ‘unlikely’ outcome is not expected to occur, an ‘unlikely’ outcome will still occur one in five times (based on a translation of 20%, e.g. Theil, 2002), according to a frequentist perspective. When an ‘unlikely’ outcome does occur, the prediction may be deemed ‘erroneous’, reflecting a misunderstanding of the nature of uncertainty. Such misunderstandings could have ramifications for the subsequent (perceived) credibility of the communicator who made such a prediction. We examine whether the effect of ‘erroneous’ predictions on perceived credibility differs according to the communication format used. Specifically, we consider verbal, numerical (point and range [wide / narrow]) and mixed format probability expressions. We consistently find that subsequent perceptions are least affected by the ‘erroneous’ prediction when it is expressed numerically, regardless of whether it is a point or range estimate. Our findings suggest numbers should be used in consequential risk communications regarding ‘unlikely’ events, wherever possible.


Jenkins, S. C., Harris, A. J., & Lark, M. (2019). When unlikely outcomes occur: the role of communication format in maintaining communicator credibility. Journal of Risk Research, 22(5), 537-554.

Journal Article Type Article
Acceptance Date Jan 24, 2018
Online Publication Date Mar 1, 2018
Publication Date 2019
Deposit Date Feb 5, 2018
Publicly Available Date Sep 2, 2019
Journal Journal of Risk Research
Print ISSN 1366-9877
Electronic ISSN 1466-4461
Publisher Routledge
Peer Reviewed Peer Reviewed
Volume 22
Issue 5
Pages 537-554
Keywords verbal probability expressions; numerical probabilities; risk communication; trust; expertise; credibility
Public URL
Publisher URL
Additional Information This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Risk Research on [date of publication], available online:


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