Verbal probabilities: Very likely to be somewhat more confusing than numbers
Bonnie Wintle, Hannah Fraser, Ben Wills, Ann Nicholson, Fiona Fidler
PLOS ONE | PUBLIC LIBRARY SCIENCE | Published : 2019
People interpret verbal expressions of probabilities (e.g. 'very likely') in different ways, yet words are commonly preferred to numbers when communicating uncertainty. Simply providing numerical translations alongside reports or text containing verbal probabilities should encourage consistency, but these guidelines are often ignored. In an online experiment with 924 participants, we compared four different formats for presenting verbal probabilities with the numerical guidelines used in the US Intelligence Community Directive (ICD) 203 to see whether any could improve the correspondence between the intended meaning and participants' interpretation ('in-context'). This extends previous work ..View full abstract
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Awarded by Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA)
Awarded by IARPA Contract
B.C. Wintle, HF, and FF were supported by a grant from the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA, https://www.iarpa.gov/), under Contract [2017-16122000002]. AEN was supported by IARPA Contract [2017-16112300008]. B.C. Wills was supported by a Maguire Fellowship from Vassar College. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of ODNI, IARPA, or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright annotation therein. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.