Biemer P P, Witt M
Survey Methods Research Program, Research Triangle Institute, NC 27709-2194, USA.
NIDA Res Monogr. 1997;167:439-76.
Direct estimates of response bias for self-reports of drug use in surveys require that essentially error free determinations of drug use be obtained for a subsample of survey respondents. The difficulty of obtaining determinations which are accurate enough for estimating validity is well-documented in the literature. Methods such as specimen (e.g., hair, urine) analysis, proxy reports, and the use of highly private and anonymous modes of interview all have to contend with error rates which may only be marginally lower than those of the parent survey. Thus, any methodology for direct validity estimation must rely to some extent on approximations and questionable assumptions. In this chapter, the authors consider a number of methods that rely solely on repeated measures data to assess response bias. Since the assumptions associated with these approaches do not require highly accurate second determinations they may be more easily satisfied in practice. One such method for bias estimation for dichotomous variables that is considered in some detail provides estimates of misclassification probabilities in the initial measurement without requiring that the second measure be accurate or even better than the first. This methodology does require, however, that two subpopulations exist which have different rates of prevalence but whose probabilities of false positive and false negative error are the same. The applicability of these methods for self-reported drug use are described and illustrated using data from the National Household Survey on Drug Abuse. In the discussion of the results, the importance of these methods for assessing the validity of self-reported drug use are examined.
在调查中，对药物使用自我报告的反应偏差进行直接估计，需要为一部分调查受访者获取基本无误差的药物使用判定结果。文献中充分记载了获取足够准确以估计效度的判定结果的难度。诸如样本（如头发、尿液）分析、代理报告以及使用高度私密和匿名访谈方式等方法，都不得不应对误差率，这些误差率可能仅略低于原始调查的误差率。因此，任何直接效度估计的方法在某种程度上都必须依赖近似值和可疑假设。在本章中，作者考虑了一些仅依靠重复测量数据来评估反应偏差的方法。由于与这些方法相关的假设并不要求高度准确的第二次判定，所以在实践中可能更容易满足。这里详细考虑的一种用于二分变量偏差估计的方法，可在不要求第二次测量准确甚至比第一次更好的情况下，估计初始测量中的错误分类概率。然而，这种方法确实要求存在两个亚群体，它们的流行率不同，但假阳性和假阴性错误的概率相同。利用来自全国药物滥用家庭调查的数据，描述并说明了这些方法在自我报告药物使用方面的适用性。在结果讨论中，考察了这些方法对评估自我报告药物使用效度的重要性。
