Purpose: A deep body of research has examined how healthcare professionals can best discuss risk information with patients, particularly those with low numeracy. It is equally important to examine how patients themselves use risk words. The current study, a subset of a larger risk communication experiment, examines the relationship between patients' qualitative and quantitative expressions of perceived risk.
Method: Patients were recruited from hospital waiting rooms (n = 65) or online (n = 100) to complete a web-based questionnaire about health risk perception and decision-making. Participants read short scenarios about their personal risk of (a) a flulike disease with a 29% chance of occurring in the short-term, and (b) a cardiac condition with a 6% chance of developing over time. After reading the stories, participants were asked to estimate their risk on a 7-item verbal scale ranging from “almost zero” to “almost certain” (verbal risk interpretation) and on a numeric scale from 0% to 100% (numeric risk interpretation).
Result: For Story 1 (29% risk), the median numeric risk interpretation was 29 and the modal verbal risk interpretation was “moderate”. For Story 2, the modal quantitative risk interpretation was 6, and the modal verbal risk was “very small”. Although verbal and numeric risk interpretation were correlated (rhos = 0.53 and 0.59, p’s < .001), there was tremendous variation. For example, “moderate” risk in Story 1 corresponded to numeric values ranging from 10% to 90%. Conversely, a risk of 29% in Story 1 was described as anything from “almost zero” to “very large,” and a risk of 6% in Story 2 was described as anything from “almost zero” to “moderate.” Although both verbal and numeric risk estimates were higher among patients with low numeracy, the correlation between them was not affected by numeracy.
Conclusion: Although patients anchored their numeric risk estimates on the number that had been presented to them by their hypothetical doctor, their verbal interpretations varied widely. These verbal expressions may reflect their understanding of the meaning of the risk (“gist”, Reyna and Brainerd 2011). It is thus extremely important that healthcare providers recognize the importance of this tremendous variability in the words patients use to interpret a single risk number.
See more of: The 34th Annual Meeting of the Society for Medical Decision Making