The Construct and Predictive Validity of a Self-Assessment Scale

Guided by the theory of interpretive validity argument, this study investigated the plausibility and accuracy of five sets of warrants which were deemed crucial to the validity of a self-assessment (SA) scale designed and used in a local EFL context. Methodologically, this study utilized both the Rasch measurement theory and structural equation modeling (SEM) to examine the five warrants and their respective rebuttals. Results from Rasch analysis indicated that the scale could reliably distinguish students at different proficiency levels. Among the 26 can-do statements in the SA scale, only one statement failed to fit the expectations of the Rasch model. Furthermore, each category was found to function as intended, though the first category was somewhat underused. Confirmatory factor analysis of the SA data supported the tenability of the Higher-Order Factor model which is consistent with the current view of L2 ability. Structural regression analysis revealed that the association between students' self-assessments and their scores on a standardized proficiency test was moderately strong. The multiple strands of evidence generated by various quantitative analyses of the SA data generally supported the validity of the SA scale. Future research, however, is warranted to examine other inferences in the validity argument structure, particularly in relation to the utility of the SA scale in English teaching and learning.