External Quality Assessor Performance in Thai Vocational Education: A Secondary Mixed-Methods Analysis of the ONESQA 2025 Stakeholder Survey

บทคัดย่อ

Abstract
External quality assurance in vocational education depends on assessors who can combine quality-assurance methodology, knowledge of occupational and institutional contexts, and relational competence. This study examined how those capabilities were perceived in Thailand through a QUAN-dominant secondary mixed-methods analysis of the 2025 ONESQA Service Satisfaction and Development Survey. The parent survey included 6,500 respondents; the present analysis focused on 44 vocational institutions and 102 vocational-education assessors, with cross-sector comparisons to early-childhood and basic-education assessors. Quantitative indicators covered satisfaction, engagement, Net Promoter Score, and confidence. The instrument development process included five-expert content review, pilot testing, and high internal-consistency estimates for the external-assessor scales (Cronbach’s α = .92–.98). Qualitative evidence was drawn from the parent report’s pooled institution and assessor focus-group strands and was used to contextualize and expand the vocational quantitative findings rather than to provide a direct vocational-specific convergence test. Because the source report did not state whether qualitative synthesis was conducted blind to the quantitative results, the integrated claims are presented as interpretive propositions rather than independent corroboration. Vocational institutions rated the external-assessor dimension highly (M = 4.67/5), including ethics (M = 4.71), expertise (M = 4.70), and fairness/professional conduct (M = 4.70). Vocational assessors also reported high satisfaction (M = 4.42/5), engagement (M = 9.24/10; NPS = 79.17), and confidence (M = 4.50/5), although each indicator was lower than the corresponding scores in the other two sectors. Concrete examples from the qualitative strand included assigning context-matched assessor teams, using calibration exercises to reduce variation in professional judgment, strengthening listening and developmental communication, providing continuous training, and creating 360-degree feedback from institutions, peers, and quality supervisors. The integrated interpretation is an "assurance-empathy asymmetry": stakeholders trusted assessors’ ethics and technical credibility, while relational and context-sensitive practice remained a latent vulnerability. The study contributes a three-part conception of vocational assessor competence and identifies feedback design as a mechanism for linking accountability with continuous improvement.

Keywords: external quality assurance; vocational education and training; assessor competence; SERVQUAL; stakeholder confidence; mixed methods; Thailand