"A 30% chance of rain tomorrow": How does the public understand probabilistic weather forecasts?
"A 30% chance of rain tomorrow": How does the public understand probabilistic weather forecasts?
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DOI：
10.1111/j.1539-6924.2005.00608.x
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发表时间：
2005-06-01
期刊：
影响因子：
3.8
通讯作者：
Katsikopoulos, KV
中科院分区：
文献类型：
--
作者：
Gigerenzer, G;Hertwig, R;Katsikopoulos, KV
天气预报说“有30%的可能性下雨”，我们认为我们明白这意味着什么。这种定量的陈述被认为是明确的，并且比定性的陈述传达更多的信息，比如“明天可能会下雨”。“然而，由于预测是以单一事件的概率表示的，它并没有指定它所指的事件类别。因此，即使是数字概率也可以被公众以多种相互矛盾的方式解释。为了弄清楚关于降雨概率的同一陈述是否会引起各种解释，我们随机调查了位于不同程度暴露于概率预测的国家的五个大都市的行人-阿姆斯特丹，雅典，柏林，米兰和纽约。他们被问到“明天下雨的可能性为30%”在多项选择和自由回答中意味着什么。只有在纽约，他们中的大多数人提供了标准的气象解释，即当天气条件像今天一样时，10种情况中有3种会在第二天下雨（至少有一丝）。在欧洲的每一个城市，这种选择都被认为是最不合适的。在欧洲，人们更喜欢的解释是明天会下雨，“30%的时间”，其次是“30%的地区”。“为了改善与公众的风险沟通，专家需要指定参考类别，即单一事件概率所指的事件类别。
The weather forecast says that there is a "30% chance of rain," and we think we understand what it means. This quantitative statement is assumed to be unambiguous and to convey more information than does a qualitative statement like "It might rain tomorrow." Because the forecast is expressed as a single-event probability, however, it does not specify the class of events it refers to. Therefore, even numerical probabilities can be interpreted by members of the public in multiple, mutually contradictory ways. To find out whether the same statement about rain probability evokes various interpretations, we randomly surveyed pedestrians in five metropolises located in countries that have had different degrees of exposure to probabilistic forecasts--Amsterdam, Athens, Berlin, Milan, and New York. They were asked what a "30% chance of rain tomorrow" means both in a multiple-choice and a free-response format. Only in New York did a majority of them supply the standard meteorological interpretation, namely, that when the weather conditions are like today, in 3 out of 10 cases there will be (at least a trace of) rain the next day. In each of the European cities, this alternative was judged as the least appropriate. The preferred interpretation in Europe was that it will rain tomorrow "30% of the time," followed by "in 30% of the area." To improve risk communication with the public, experts need to specify the reference class, that is, the class of events to which a single-event probability refers.