A Glance at Coefficient Alpha with an Eye Towards Robustness Studies: Some Mathematical Notes and a Simulation Model

In many testing situations the use of parallel forms or test-retest reliability coefficients is impractical. Viable alternatives to these approaches are the internal consistency coefficients. One of the most commonly used internal consistency coefficients is Cronbachs coefficient alpha. The purpose of this paper is to discuss the robustness of coefficient alpha. To begin, I will provide a derivation of coefficient alpha. In the process of the derivation, I will try to provide insight into alpha's potential robustness. The paper will close with a simulation algorithm for studying alphas robustness. Paper 99-1 of the Edgeworth Series in Quantitative Behavioral Science. When citing this paper please use the following format (for APA style): Zumbo, B. D. (1999). A glance at coefficient alpha with an eye towards robustness studies: Some mathematical notes and a simulation mode