Collaborative Reseach: Model-based Methods for Debiasing Individual Probability Assessments: Theory, Experiments, and Application to Mississippi River Delta Restoration

专家经常被要求提供判断，为私营部门和公共政策决策提供信息。这种判断可以单独使用，也可以与科学模型一起使用，以估计诸如能源市场变化、未来二氧化碳排放水平、全球温度变化或在美国登陆的飓风数量等事件的概率。专家判断是必不可少的，因为过去的数据可能无法获得，或者由于条件的变化而不直接相关。然而，从心理学研究中我们知道，在做出这种概率判断时，人们会使用心理捷径或启发式。启发式会扭曲人们表达判断的方式，导致概率上无意的偏差，系统性地扭曲了个人陈述的概率。这些认知偏差是研究的重点，而不是故意的偏差，其中表达的概率被故意扭曲，以便与系统博弈。当概率是科学模型或决策的输入时，最小化专家概率的认知偏差是必不可少的，而这些决策必须在不等待完美信息的情况下做出。这项研究的目的是开发数学模型和统计程序，分析人员可以利用这些模型和统计程序来估计个人的偏见程度，从而量化消除这些偏见的调整。这项研究主要关注三种认知偏差：过度精确，即过于肯定某一特定事件会发生的倾向；分区依赖，即判断概率不恰当地依赖于不确定变量范围的划分方式；而结转，一种排序效应，其中一个个体？所陈述的概率可能受到先前判断的影响。偏差测量和消除方法将在实验环境中开发和测试，使用大量参与者。实验结果将显示在各种情况下偏差的程度，以及该方法消除偏差的有效性。这项研究将使专家在从事公共和私营部门风险分析时，能够提供更好地代表他们的信念和知识的概率，而不受偏见的扭曲。潜在的应用包括数据稀缺，再加上高风险，使得使用专家判断必不可少的决策。这包括商业决策的许多领域，以及与气候变化和恐怖主义风险有关的高风险政策决策。

Experts are often asked to provide judgments to inform both private sector and public policy decisions. Such judgments may be used alone or with scientific models to estimate the probability of events such as changes in energy markets, levels of future carbon dioxide emissions, global temperature change, or the number of hurricanes to make landfall in the United States. Expert judgments are essential because past data may either be unavailable or not directly relevant due to changing conditions. From psychological research, however, we know that when making such probability judgments, people use mental short-cuts, or heuristics. The heuristics skew how people express judgments, resulting in unintentional biases in probabilities that systematically distort an individual's stated probabilities. These cognitive biases are the focus of the research, rather than intentional biases in which expressed probabilities are deliberately distorted in order to game the system. Minimizing cognitive biases in expert probabilities is essential when the probabilities are inputs to scientific models or to decisions that must be made without waiting for perfect information. The objective of this research is to develop mathematical models and statistical procedures with which an analyst can estimate the degree of bias for an individual and thereby quantify adjustments that would eliminate those biases. The research focuses on three cognitive biases: overprecision, the tendency to be too sure that a particular event will occur; partition dependence, in which judged probabilities depend inappropriately on how the range of the uncertain variable is divided; and carryover, an ordering effect in which an individual?s stated probabilities may be affected by previous judgments. The bias measurement and debiasing methods are to be developed and tested in experimental settings using a large group of participants. The experimental results will show the extent of the biases under various circumstances, and the effectiveness of the method for removing the bias. This research will enable experts to provide probabilities that better represent their beliefs and knowledge, undistorted by bias, when engaged in public- and private-sector risk analyses. Potential applications include decisions in which data scarcity, coupled with high stakes, make the use of expert judgments essential. These include many areas of business decision making, as well as high-stakes policy decisions concerning, for instance, climate change and terrorism risk.