Abstract：
OBJECTIVE: In the cognitive process of establishing a diagnosis, the performance of a diagnostician can be characterized in terms of sensitivity and specificity. The aims of the present study are to analyze in quantitative terms how cognitive bias affects the performance of a diagnostician, and how a diagnostician\'s biased decision making is further influenced by personal cost-benefit considerations.
METHODS: The test matrices of two sequential diagnostic tests are manipulated according to the rules of linear algebra, using multiplication of the second with the first test matrix to calculate their joint test characteristics. The decision tree and receiver operating characteristic (ROC) of a biased and unbiased diagnostician are used to calculate which combination of test characteristics maximizes the expected utility value.
RESULTS: Biased diagnosticians cannot establish a diagnosis beyond their own limited or distorted level of understanding. An unbiased and a biased diagnostician alike adjust their choice of test characteristics according to their different cost-benefit estimation of the various test outcomes. From the perspective of an unbiased diagnostician, the choices made by a biased diagnostician appear to invert reality. However, the same appearance of inverted reality is perceived by the biased diagnostician, judging the choices made by the unbiased diagnostician.
CONCLUSIONS: As a general principle, human testers cannot test beyond their own level of understanding. They only see what they know. As they base their judgment on preconceived notions about the utilities associated with different test outcomes, human testers also tend to only know what they want to know.
METHODS: The test matrices of two sequential diagnostic tests are manipulated according to the rules of linear algebra, using multiplication of the second with the first test matrix to calculate their joint test characteristics. The decision tree and receiver operating characteristic (ROC) of a biased and unbiased diagnostician are used to calculate which combination of test characteristics maximizes the expected utility value.
RESULTS: Biased diagnosticians cannot establish a diagnosis beyond their own limited or distorted level of understanding. An unbiased and a biased diagnostician alike adjust their choice of test characteristics according to their different cost-benefit estimation of the various test outcomes. From the perspective of an unbiased diagnostician, the choices made by a biased diagnostician appear to invert reality. However, the same appearance of inverted reality is perceived by the biased diagnostician, judging the choices made by the unbiased diagnostician.
CONCLUSIONS: As a general principle, human testers cannot test beyond their own level of understanding. They only see what they know. As they base their judgment on preconceived notions about the utilities associated with different test outcomes, human testers also tend to only know what they want to know.
摘要：
目的：在建立诊断的认知过程中，诊断医师的表现可以通过敏感性和特异性来表征.本研究的目的是定量地分析认知偏见如何影响诊断医生的表现，以及诊断医生的偏见决策如何进一步受到个人成本效益考虑的影响。
方法：根据线性代数的规则操纵两个顺序诊断测试的测试矩阵，使用第二个与第一个测试矩阵的乘法来计算它们的联合测试特性。有偏和无偏诊断医生的决策树和接收者工作特性（ROC）用于计算哪种测试特性组合使期望效用值最大化。
结果：有偏见的诊断医生无法确定超出其自身有限或扭曲的理解水平的诊断。无偏见和有偏见的诊断医生都会根据他们对各种测试结果的不同成本收益估计来调整他们对测试特征的选择。从一个不偏不倚的诊断医生的角度来看，一个有偏见的诊断医生做出的选择似乎颠覆了现实。然而,有偏见的诊断医生会感知到相同的倒置现实，判断无偏见的诊断医生做出的选择。
结论：作为一般原则，人类测试人员无法测试超出自己的理解水平。他们只看到他们所知道的。由于他们的判断基于与不同测试结果相关的效用的先入为主的观念，人类测试人员也往往只知道他们想知道什么。
方法：根据线性代数的规则操纵两个顺序诊断测试的测试矩阵，使用第二个与第一个测试矩阵的乘法来计算它们的联合测试特性。有偏和无偏诊断医生的决策树和接收者工作特性（ROC）用于计算哪种测试特性组合使期望效用值最大化。
结果：有偏见的诊断医生无法确定超出其自身有限或扭曲的理解水平的诊断。无偏见和有偏见的诊断医生都会根据他们对各种测试结果的不同成本收益估计来调整他们对测试特征的选择。从一个不偏不倚的诊断医生的角度来看，一个有偏见的诊断医生做出的选择似乎颠覆了现实。然而,有偏见的诊断医生会感知到相同的倒置现实，判断无偏见的诊断医生做出的选择。
结论：作为一般原则，人类测试人员无法测试超出自己的理解水平。他们只看到他们所知道的。由于他们的判断基于与不同测试结果相关的效用的先入为主的观念，人类测试人员也往往只知道他们想知道什么。
