University of Granada, Experimental Psychology, Campus Universitario de Cartuja s/n, 18071 Granada, Spain.
Soc Sci Med. 2010 Apr;70(7):1019-25. doi: 10.1016/j.socscimed.2009.11.031. Epub 2010 Jan 28.
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.
许多人在理解治疗风险降低所需的数字概念方面存在困难。视觉辅助工具已被提出作为提高理解能力的一种有前途的方法。在对来自两个不同国家（美国和德国）的概率性、全国代表性样本的调查中，我们比较了在绝对风险降低或相对风险降低格式中向数字信息添加不同类型的视觉辅助工具（仅代表受影响个体或整个风险人群的图标数组和条形图）的效果。我们还分析了人们的计算能力和图形读写能力是否会影响视觉辅助工具的效果。我们的结果表明，无论是添加图标数组还是条形图，都能显著提高准确性。当视觉辅助工具描绘整个风险人群时，效果最佳。重要的是，对于计算能力较低但图形读写能力相对较高的参与者来说，视觉辅助工具最有用。基于先前的研究表明，对数字信息理解的问题通常不在于人们的思维，而在于问题的表示，我们的结果表明，视觉辅助工具有助于修正对治疗风险降低的错误期望。我们的结果对医疗实践具有重要意义。
