title: Who profits from visual aids: overcoming challenges in people's understanding of risks [corrected].
abstract: Many people have difficulties grasping numerical concepts that are prerequisites for understanding treatment risk reduction. Visual aids have been proposed as a promising method for enhancing comprehension. In a survey of probabilistic, nationally representative samples in two different countries (United States and Germany), we compared the effectiveness of adding different types of visual aids (icon arrays and bar graphs representing either affected individuals only or the entire population at risk) to the numerical information in either an absolute or a relative risk reduction format. We also analyzed whether people's numeracy and graphical literacy skills affected the efficacy of the visual aids. Our results showed large improvements in accuracy both when icon arrays and when bar graphs were added to numerical information. Highest increases were achieved when the visual aids depicted the entire population at risk. Importantly, visual aids were most useful for the participants who had low numeracy but relatively high graphical literacy skills. Building on previous research showing that problems with understanding numerical information often do not reside in people's minds, but in the representation of the problem, our results show that visual aids help to modify incorrect expectations about treatment risk reduction. Our results have important implications for medical practice.
authors.affiliation: University of Granada, Experimental Psychology, Campus Universitario de Cartuja s/n, 18071 Granada, Spain. rretamer@ugr.es
authors.forename: Rocio
authors.initials: R
authors.lastname: Garcia-Retamero
authors.forename: Mirta
authors.initials: M
authors.lastname: Galesic
mesh_terms: D000328:Adult; D000368:Aged; D001296:Audiovisual Aids; D032882:Comprehension; D003431:Cross-Cultural Comparison; D005260:Female; D005858:Germany; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008488:Medical Illustration; D008875:Middle Aged; D010353:Patient Education as Topic / Q000379:methods*; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D014481:United States