B. Fischhoff, W.J.A. Bruine de Bruin

Research output: Contribution to journalArticleAcademicpeer-review

204 Citations (Scopus)


Several recent surveys have asked respondents to estimate the probabilities of relatively unlikely events, such as dying from breast cancer and smoking. Examination of their response distributions reveals a seemingly inappropriate ‘blip’ at 50. The two studies reported here indicate that it reflects a response artifact associated with open-ended probability scales. The blip vanishes when a response scale with explicit response options is offered. Apparently, the open-ended format leads some people to use the 50% option as ‘fifty–fifty’, an expression of having no idea as to the answer. As a result, the accuracy of people's reported beliefs depends on the response scale used, as well as on how it evokes and channels such feelings of epistemic uncertainty.
Original languageEnglish
Pages (from-to)149-163
Number of pages15
JournalJournal of Behavioral Decision Making
Publication statusPublished - 1999


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