Comparing what to what, on what scale? The impact of item comparisons and reference points in communicating risk and uncertainty

Tim Rakow, Emily Blackshaw, Christina Pagel, David S Spiegelhalter

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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The mandated public availability of individual hospital's audit data for children's heart surgery in the UK creates a challenging scenario for communicating these complex and sensitive data to diverse audiences. On the basis of this scenario, we conducted three experiments with the aim of understanding how best to help lay people understand these data and the practical goal of improving the public presentation of these data. The experiments compared different outcome measures for displaying the survival rate (percentage scale versus the ratio of the predicted/observed rates) and presentation formats (individual hospital versus all hospitals shown) for outcomes data presented relative to prediction intervals generated by a risk model that adjusts for case mix. Our data highlight how easily inappropriate comparisons can influence evaluations of complex data: for instance, both a survival ratio of 1 and the presence of other hospitals seemingly provided reference points that resulted in inappropriately harsh evaluations of some hospitals. By drawing on evaluability theory, we demonstrate how to enhance people's understanding of these complex data while also discouraging inappropriate comparisons, which has implications for communicating risk and uncertainty and for choice architecture design in a range of contexts.
Original languageEnglish
Pages (from-to)547-561
JournalJournal of Behavioral Decision Making
Issue number4
Early online date11 Jan 2018
Publication statusPublished - Oct 2018


  • Risk communication
  • Uncertainty
  • Prediction intervals
  • Reference-dependent evaluation
  • Evaluability


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