Becker Gilbert
Department of Psychology, University of Winnipeg, Manitoba, Canada.
Psychol Rep. 2008 Oct;103(2):545-65. doi: 10.2466/pr0.103.2.545-565.
This article addresses deficiencies in the most widely used estimators of reliability and draws attention to the reason that this issue is important. Accurate calibration of relationships between constructs is critical to theory development. Unless workers have accurate estimates of scale reliability, accurate estimates of those relationships will not be forthcoming because the classical disattenuation formula requires them. This article shows that classical test theory can easily accommodate the delineation of its error component E in test scores into two sources, inconsistency across content (E1) and inconsistency across time (E2). Viewed from this extended model, the alternate forms approach to reliability estimation is complete in that it gauges simultaneously both sources of error. Because that approach is rarely used today for that purpose, the integrity of estimation has been lost. In its place arose estimators of partial reliability--those for estimating generalizability over one medium or the other, but not both, thereby precluding the additivity of error components. Recent developments promise to restore the integrity of the alternate forms approach without the need for alternate forms and suggest an additive alternative to the current nonadditive coefficient of stability.
本文探讨了最广泛使用的信度估计方法的不足之处，并提请注意这一问题为何重要。对构念之间关系进行准确校准对于理论发展至关重要。除非工作者对量表信度有准确估计，否则无法得出这些关系的准确估计，因为经典的去衰减公式需要这些估计。本文表明，经典测试理论能够轻松地将测试分数中的误差成分E划分为两个来源，即内容不一致性（E1）和时间不一致性（E2）。从这个扩展模型来看，交替形式信度估计方法是完备的，因为它能同时测量这两个误差来源。由于如今很少为此目的使用该方法，估计的完整性已丧失。取而代之的是部分信度估计方法——用于估计在一种媒介或另一种媒介上的可推广性，但不是两者兼顾，从而排除了误差成分的可加性。最近的进展有望恢复交替形式方法的完整性，而无需使用交替形式，并为当前非可加性的稳定性系数提供一种可加性替代方案。
