Zikmund-Fisher Brian J, Fagerlin Angela, Ubel Peter A
VA Health Services Research and Development Center for Practice Management and Outcomes Research, VA Ann Arbor Healthcare System, Ann Arbor, MI 48109, USA.
Risk Anal. 2005 Jun;25(3):589-95. doi: 10.1111/j.1539-6924.2005.00626.x.
Reports of randomized clinical trials often use survival curves to summarize clinical outcomes over time and graphically demonstrate evidence of treatment effectiveness. Survival curves can also be used in patient communications to display how health risks accumulate over time. In a randomized survey experiment, administered online, we tested whether people viewing survival curves appropriately adjust their risk perceptions to account for the duration shown. Internet users (N= 864) were recruited from a demographically balanced U.S. panel. Participants read about a hypothetical disease and then viewed one of four survival graphs that displayed mortality risks with and without treatment. Survival graphs showed either a visually large or visually small difference between treatments and were labeled to represent either 5-year or 15-year risk statistics. Participants then provided ratings of disease seriousness, as well as treatment effectiveness for each possible treatment. Variations in ratings corresponded more with visual dissimilarity than with changes in the statistical risk exhibited, with participants perceiving somewhat greater disease seriousness and significant differences in treatment effectiveness in large visual difference graphs. We conclude that when people interpret survival curves, they often fail to sufficiently account for the timeframe represented and perceive more risk and larger differences when identical risks are displayed over longer periods of time. We recommend that all presentations of survival graphics, whether to patients, physicians, or scientists, emphasize duration information (e.g., in the title) and remind readers that attending to graph axis labels is the only way to pierce these visual illusions.
随机临床试验报告通常使用生存曲线来总结一段时间内的临床结果，并以图形方式展示治疗效果的证据。生存曲线也可用于与患者沟通，以展示健康风险如何随时间累积。在一项在线进行的随机调查实验中，我们测试了观看生存曲线的人是否会适当调整他们的风险认知，以考虑所显示的持续时间。从一个人口统计学平衡的美国样本中招募了互联网用户（N = 864）。参与者阅读了一种假设疾病的相关内容，然后观看了四个生存图之一，这些图展示了有治疗和无治疗情况下的死亡风险。生存图显示治疗之间在视觉上有大或小的差异，并标注为代表5年或15年的风险统计数据。参与者随后对疾病的严重程度以及每种可能治疗的治疗效果进行了评分。评分的差异更多地与视觉差异相关，而不是与所展示的统计风险变化相关，在视觉差异大的图中，参与者认为疾病严重程度略高，治疗效果有显著差异。我们得出结论，当人们解读生存曲线时，他们往往没有充分考虑所代表的时间范围，并且当相同的风险在更长时间内展示时，会感知到更多的风险和更大的差异。我们建议，无论是向患者、医生还是科学家展示生存图表，都应强调持续时间信息（例如在标题中），并提醒读者关注图表轴标签是识破这些视觉错觉的唯一方法。
