Fries James F, Krishnan Eswar
Stanford University School of Medicine, Palo Alto, CA 94304, USA.
J Clin Epidemiol. 2009 Aug;62(8):779-80. doi: 10.1016/j.jclinepi.2008.12.001. Epub 2009 Mar 17.
Patient self-reported disability outcomes, measured using instruments such as the Health Assessment Questionnaire Disability Index (HAQ-DI) form a foundation for clinical studies of several conditions, notably arthritis. These instruments are "static" because the instrument is the same in all applications. Although generally performing well, they may fail at extremes of disability, the so-called floor and ceiling effects. Another limitation is the degree of measurement error, the signal-to-noise ratio. These two issues drive down the statistical power of clinical trials and increase their expense.
患者自我报告的残疾结果，通过诸如健康评估问卷残疾指数（HAQ-DI）等工具进行测量，构成了多种病症（尤其是关节炎）临床研究的基础。这些工具是“静态的”，因为在所有应用中工具都是相同的。尽管通常表现良好，但在残疾程度的极端情况下，即所谓的地板效应和天花板效应，它们可能会失效。另一个局限性是测量误差程度，即信噪比。这两个问题降低了临床试验的统计效力并增加了试验成本。
