Informant accuracy is a pervasive issue in the social sciences and persists through the ongoing use of self-report measures of behaviors that are subject to recall errors. The current study reports findings from methods we used to measure substance use among adolescents in South India. We used a repeated-measures, mixed-methods design that began with semistructured interviews (N = 60) to determine the substances used by adolescents. Next, adolescents were recruited to participate in a four-week study that assessed self-reported substance use at three time points and urinary cotinine, a nicotine metabolite, at two time points. Fifty-six participants completed the study protocol. Findings revealed that during the last phase of the study, participants were more willing to admit using substances. Our results add to existing literature that demonstrates the need to move beyond self-reported data of consumption, and to consider using repeated measures, direct observation of behavior, and biometric markers of behavior to ensure more accurate assessments of sensitive topics.

中文翻译：

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物质使用研究中的混合方法和重复测量：对知情人准确性的影响

线人的准确性是社会科学中普遍存在的问题，并且通过不断使用自我报告的行为来衡量容易发生回忆错误的行为而持续存在。当前的研究报告了我们用来衡量印度南部青少年物质使用情况的方法的结果。我们使用从半结构化访谈（N = 60）开始的重复测量、混合方法设计来确定青少年使用的物质。接下来，青少年被招募参加一项为期 4 周的研究，该研究评估了三个时间点的自我报告物质使用情况和两个时间点的尿可替宁（一种尼古丁代谢物）。56 名参与者完成了研究方案。结果显示，在研究的最后阶段，参与者更愿意承认使用过物质。