University of Erfurt, Erfurt, Germany.
Risk Anal. 2013 Oct;33(10):1812-28. doi: 10.1111/risa.12025. Epub 2013 Mar 6.
The RISK of an event generally relates to its expected severity and the perceived probability of its occurrence. In RISK research, however, there is no standard measure for subjective probability estimates. In this study, we compared five commonly used measurement formats--two rating scales, a visual analog scale, and two numeric measures--in terms of their ability to assess subjective probability judgments when objective probabilities are available. We varied the probabilities (low vs. moderate) and severity (low vs. high) of the events to be judged as well as the presentation mode of objective probabilities (sequential presentation of singular events vs. graphical presentation of aggregated information). We employed two complementary goodness-of-fit criteria: the correlation between objective and subjective probabilities (sensitivity), and the root mean square deviations of subjective probabilities from objective values (accuracy). The numeric formats generally outperformed all other measures. The severity of events had no effect on the performance. Generally, a rise in probability led to decreases in performance. This effect, however, depended on how the objective probabilities were encoded: pictographs ensured perfect information, which improved goodness of fit for all formats and diminished this negative effect on the performance. Differences in performance between scales are thus caused only in part by characteristics of the scales themselves-they also depend on the process of encoding. Consequently, researchers should take the source of probability information into account before selecting a measure.
事件的风险通常与预期的严重程度和其发生的感知概率有关。然而，在风险研究中，对于主观概率估计，没有标准的测量方法。在这项研究中，我们比较了五种常用的测量格式——两种评分量表、一种视觉模拟量表和两种数字测量方法——在有客观概率的情况下，它们评估主观概率判断的能力。我们改变了要判断的事件的概率（低与中）和严重程度（低与高），以及客观概率的呈现方式（单个事件的顺序呈现与聚合信息的图形呈现）。我们采用了两个互补的拟合优度标准：客观概率和主观概率之间的相关性（敏感性），以及主观概率与客观值的均方根偏差（准确性）。数字格式通常优于所有其他方法。事件的严重程度对表现没有影响。一般来说，概率的上升会导致表现的下降。然而，这种效应取决于客观概率的编码方式：象形图确保了完整的信息，这提高了所有格式的拟合优度，并减轻了对表现的负面影响。因此，量表之间的表现差异部分是由量表本身的特点造成的——它们也取决于编码过程。因此，在选择测量方法之前，研究人员应该考虑概率信息的来源。
