Understanding Jurors Use of Highly Diagnostic Statistical Evidence

理解和改进陪审员对高度诊断性统计证据的使用在法庭上围绕科学证据使用的争论中，没有比陪审员如何解释和使用与法医科学证据有关的微小统计数据更紧迫的问题了。 例如，许多人认为这些统计数据在犯罪嫌疑人与从暴力犯罪现场找到的DNA证据相匹配的情况下具有说服力。 也就是说，他们相信，在听到从千分之一到十亿分之一的巧合匹配统计数据后，陪审员将确信匹配的嫌疑人确实是恢复的DNA证据的来源。 另一些人认为陪审员会被数字弄糊涂，不会发现证据令人信服。谁是对的？ 我自己对模拟陪审员的初步研究表明，统计证据的呈现方式可能会对法律的决策者如何思考和使用证据产生强大的影响。 我提供了一个描述性的理论和两个实验来帮助理解法律决策者如何对高度诊断性的统计证据做出反应。这个理论--被称为范例线索理论--预测了决策者何时会发现统计匹配证据相对有力和有说服力，何时不会。 它认为，与统计匹配证据的强度和说服力相关的判断和选择是由巧合匹配样本的可用性指导的。 在决策者可以很容易地产生机会匹配的例子的程度上，证据似乎不那么令人信服的身份证明。 这个理论框架足够广泛，足以理解人们如何看待许多低概率事件，如一个人中彩票的机会或环境灾难或遗传疾病带来的风险。 这些数据也足够精确，可以帮助我们理解陪审员何时会被被告关于DNA匹配纯属巧合的论点所说服。这些数据将对各种各样的支持者有用，从必须制定统计证据可接受性的指示和标准的法官和政策制定者，到必须找到沟通匹配含义的方法的科学家、执法人员和律师。

Understanding and Improving Jurors' Use of Highly Diagnostic Statistical EvidenceJonathan J. KoehlerThere is no more pressing issue in the controversy that swirls around the use of scientific evidence in the courtroom than how jurors interpret and use the tiny statistics that arise in connection with forensic science evidence. For example, many people assume that these statistics are persuasive in cases where a criminal suspect matches traces of DNA evidence recovered from the scene of a violent crime. That is, they believe that after hearing coincidental match statistics that range from 1 in thousands to 1 in billions, jurors will be convinced that the matching suspects are indeed the source of the recovered DNA evidence. Others believe that jurors will be confused by the numbers and will not find the evidence compelling.Who's right? My own preliminary research with mock jurors indicates that the way in which statistical evidence is presented may exert a powerful effect on how legal decision makers think about and use the evidence. I offer a descriptive theory and two experiments to help understand howlegal decision makers respond to highly diagnostic statistical evidence.The theory -- called exemplar cueing theory -- predicts when decisionmakers will find statistical match evidence relatively strong andpersuasive and when not. It holds that judgments and choices related tothe strength and persuasiveness of statistical match evidence are guided bythe availability of coincidental match exemplars. To the extent decisionmakers can easily generate examples of chance matches, the evidence willseem less compelling as proof of identity. This theoretical framework is broad enough for understanding how peoplethink about many low probability events such as one's chances of winningthe lottery or the risks posed by environmental catastrophe or geneticdisease. It is also sufficiently refined that it may help us understandwhen jurors will be persuaded by a defendant's argument that a DNA match ispurely coincidental.These data will be useful to a variety of constituencies, from the judgesand policy makers who must develop instructions and standards for theadmissibility of statistical evidence, to the scientists, law enforcementofficers, and attorneys who must find ways to communicate the meaning of amatch.