Investigating the presentation of uncertainty in an icon array: A randomized trial

BACKGROUND: Clinicians are often advised to use pictographs to communicate risk, but whether they offer benefits when communicating risk imprecision (e.g., 65%-79%) is unknown. PURPOSE: To test whether any of three approaches to visualizing imprecision would more effectively communicate breast and ovarian cancer risk for BRCA1 pathogenic variant carriers. METHODS: 1,300 UK residents were presented with a genetic report with information about BRCA1-related risks, with random assignment to one of four formats: no visualization (text alone), or a pictograph using shaded icons, a gradient, or arrows marking range endpoints. We also tested pictographs in two layouts. Analysis of variance (ANOVA) and regression was employed. RESULTS: There was no effect of format. Participants shown pictographs vs. text alone had better uptake of breast cancer risk messages (p < .05, η(2) = 0.003). Pictographs facilitated memory for the specific amount of risk (p < 0.001, η(2) = 0.019), as did the tabular layout. Individuals not having completed upper secondary education may benefit most. CONCLUSIONS: We found weak evidence in favor of using simple pictographs with ranges to communicate BRCA risk (versus text alone), and of the tabular layout. INNOVATION: Testing different ways of communicating imprecision within pictographs is a novel and promising line of research.