1.1 本规程描述了估计瑟斯顿判别距离（即， d '值），从两个样本上获得的数据。本文介绍了四种强制选择方法（即三角形、duo-trio、3-alternative-forced-choice（或3-AFC）和2-AFC（也称为方向差测试））、A/Not-A方法、相同-不同方法以及从有序类别量表获得的数据的程序。估计方差的程序 d '也被提出。因此，可以计算以下各项的置信区间和统计检验: d '. 1.2 本文件中的程序仅适用于一维、等效- 方差模型。其他更复杂的瑟斯顿模型涉及多个维度和不等方差，但本标准未涉及。强制选择方法的程序仅限于二分法响应。A/Not-A方法的过程假设两个样本的样本大小相等。相同-不同方法的过程假设匹配和非匹配样本对的样本大小相同。对于所有方法，只考虑未重复的测试。（每个评估员进行多次（即重复）评估的测试需要不同的分析。） 1.3 瑟斯顿标度是一种基于概率模型测量两个样本之间感知差异的方法，用于分类选择决策。 感知差异的大小δ可以使用本实践中描述的方法从评估员的分类选择中估计（参见 附录X3 有关瑟斯顿标度的更详细描述）。 1.4 理论上，瑟斯顿δ不取决于用于测量两个样本之间差异的方法。因此，δ提供了一个通用的测量尺度，用于比较在各种测试条件下测量的样本。例如，瑟斯顿标度可用于比较在不同测试条件下测量的产品，比较评估相同样品（使用相同或不同测试方法）的面板（经过培训的、消费者或两者），并比较测试方法对表现出固定感官差异的样品的辨别能力。 1.5 本标准可能涉及危险材料、操作和设备。本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1 在该模型的假设下，测量两个样本（无论是整体还是特定属性）之间感知差异的瑟斯顿模型方法独立于用于收集数据的感官方法。 将从不同试验方法获得的结果转换为 d “数值允许评估样本之间的相对差异，而无需直接相互比较样本，或对所有样本对使用相同的测试方法。 5.2 瑟斯顿标度已应用于: 5.2.1 创建历史数据库，以跟踪生产样品和参考样品在不同测试方法用于测量差异的不同时期之间的差异， 5.2.2 比较不同用户群体和消费者群体的相对敏感性， 5.2.3 比较使用不同测量技术的经过培训的面板， 5.2.4 比较消费者与经过培训的小组的相对敏感性， 5.2.5 比较不同的消费者测试方法（例如，CLT与HUT、偏好与享乐量表等），以及 5.2.6 比较不同的判别测试方法。

1.1 This practice describes procedures to estimate Thurstonian discriminal distances (that is, d ' values) from data obtained on two samples. Procedures are presented for four forced-choice methods (that is, the triangle, the duo-trio, the 3-alternative-forced-choice (or 3-AFC) and the 2-AFC (also called the directional difference test)), the A/Not-A method, the Same-Different method and for data obtained from ordered category scales. Procedures for estimating the variance of d ' are also presented. Thus, confidence intervals and statistical tests can be calculated for d '. 1.2 The procedures in this document pertain only to the unidimensional, equal-variance model. Other, more complicated Thurstonian models, involving multiple dimensions and unequal variances exist but are not addressed in this standard. The procedure for forced-choice methods is limited to dichotomous responses. The procedure for the A/Not-A method assumes equal sample sizes for the two samples. The procedure for the Same-Different method assumes equal sample sizes for the matched and unmatched pairs of samples. For all methods, only unreplicated tests are considered. (Tests in which each assessor performs multiple (that is, replicated) evaluations require different analyses.) 1.3 Thurstonian scaling is a method for measuring the perceptual difference between two samples based on a probabilistic model for categorical choice decision making. The magnitude of the perceived difference, δ, can be estimated from the assessors' categorical choices using the methods described in this practice (See Appendix X3 for a more detailed description of Thurstonian scaling). 1.4 In theory, the Thurstonian δ does not depend on the method used to measure the difference between two samples. As such, δ provides a common scale of measure for comparing samples measured under a variety of test conditions. For example, Thurstonian scaling can be used to compare products measured under different test conditions, to compare panels (trained, consumer or both) that have evaluated the same samples (using the same or different test methods) and to compare test methods on their ability to discriminate samples that exhibit a fixed sensory difference. 1.5 This standard may involve hazardous materials, operations and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 Under the assumptions of the model, the Thurstonian model approach to measuring the perceived difference between two samples (whether overall or for a specific attribute) is independent of the sensory method used to collect the data. Converting results obtained from different test methods to d ' values permits the assessment of relative differences among samples without requiring that the samples be compared to each other directly or that the same test methods be used for all pairs of samples. 5.2 Thurstonian scaling has been applied to: 5.2.1 Creating a historical database to track differences between production and reference samples over periods in which different test methods were used to measure the difference, 5.2.2 Comparing the relative sensitivities of different user groups and consumer segments, 5.2.3 Comparing trained panels that use different measuring techniques, 5.2.4 Comparing the relative sensitivities of consumers versus trained panels, 5.2.5 Comparing different methods of consumer testing (for example, CLT versus HUT, preference versus hedonic scales, etc.), and 5.2.6 Comparing different discrimination test methods.