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Yasmina Okan - Best Practice for presenting probabilities in patient decision aids

Date
Yasmina Okan - Best Practice for presenting probabilities in patient decision aids

This work reflects the collaboration of a panel of international experts on risk communication from different institutions across Australia (University of Sydney), the Netherlands (Amsterdam UMC), and the US (University of Oregon, Tufts University, University of Utah, University of Michigan, Maine Medical Center Research Institute). The reference and abstract follow.

Bonner, C., Trevena, L., Gaissmaier, W., Han, P., Okan, Y., Ozanne, E., Peters, E., Timmermans, D., & Zikmund-Fisher, B, J. (in press). Current best practice for presenting probabilities in patient decision aids: Fundamental principles. Medical Decision Making

Background: Shared decision making requires evidence to be conveyed to the patient in a way they can easily understand and compare. Patient decision aids facilitate this process. This paper reviews current evidence for how to present numerical probabilities within patient decision aids.

Methods: Following the 2013 review method, we assembled a group of 9 international experts on risk communication across Australia, Germany, the Netherlands, UK, and USA. We expanded the topics covered in the first review to reflect emerging areas of research. Groups of 2-3 authors reviewed relevant literature based on their expertise and wrote each section before review by the full authorship team.

Results: Of 10 topics identified, we present 5 fundamental issues in this paper. While some topics resulted in clear guidance (presenting the chance an event will occur, addressing numerical skills), other topics (context/evaluative labels, conveying uncertainty, risk over time) continue to have evolving knowledge bases. We recommend presenting numbers over a set time period with a clear denominator, using consistent formats between outcomes and interventions to enable unbiased comparisons, and interpreting the numbers for the reader to meet the needs of varying numeracy.

Discussion: Understanding how different numerical formats can bias risk perception will help decision aid developers communicate risks in a balanced, comprehensible manner, and avoid accidental ‘nudging’ towards a particular option. Decisions between probability formats need to consider the available evidence and user skills. The review may be useful for other areas of science communication where unbiased presentation of probabilities is important.