VIETTESOL INTERNATIONAL CONVENTION 2025

In 2020, MOET issued a three-tiered holistic assessment scale for foreign language teacher competency as a guideline for educational institutions nationwide to facilitate their teacher recruitment and professional development. However, no research to date has validated this high-stakes scale and the present study filled this gap. To this end, it employed Rasch-based evidence generated from the self-rated responses of 345 in-service teachers in Vietnam to the scale as well as those from 75 of their direct supervisors to inspect five major aspects of Messickian construct validity: Content, Substantive, Structural, Generalizability and External (1995). The results showed that the scale could sufficiently measure the target ability – foreign language teaching competency – of an overwhelming 341 out of the 345 teachers (99%) and there were three statistically distinct groups of item difficulty in the item hierarchy. Scale items and teachers performed as predicted by a priori hypotheses and displayed good fit to the Rasch model. Principal Component Analysis indicated that all items formed a fundamentally unidimensional construct, suggesting that the scale only measured one meaningful dimension. The evidence for the invariance in item calibration and person measure as well as the scale’s external reliability enabled the generalization of score properties and interpretations across scale portions, populations and contexts. Results from the teacher and supervisor interview data analyses suggested that the scale was a useful tool facilitating their recruitment process as well as their professional development practice. These findings altogether substantiate the scale’s construct validity and thus it appears useful for its intended purposes.