Meta-Analysis of Coefficient Alpha: Empirical Demonstration Using English Language Teaching Reflection Inventory

Abstract

Cronbach’s alpha is a reliability coefficient commonly reported in second language (L2) and English language teaching (ELT) studies. The alpha coefficient provides information on the internal consistency of a measuring instrument. The reported alpha coefficients are obtained from, and apply only to, the research sample. However, the estimation of the alpha coefficient for the population has not received the attention of L2 and ELT researchers. This study aims to provide an overview of the alpha coefficient estimation procedure of a measuring instrument for a population with the reliability generalization method, commonly known as alpha coefficient meta-analysis. An example alpha coefficient meta-analysis study—using empirical data of the 29-item English Language Teaching Reflection Inventory (ELTRI) from 27 independent study samples—was conducted to provide an overview of the procedure for applying the method and the information that needs to be reported from the results of the analysis. The results of the study using a random-effect model show that the population alpha of ELTRI was 0.872, indicating excellent reliability; this is followed by application of a mixed-effect model that shows that article type and means of teaching experience significantly impacted ELTRI reliability. Implications for future research are discussed.