BACKGROUND: Cognitive engagement predicts student achievement, yet mechanisms remain underexamined. Using SEM in Vietnam, we test direct and mediated effects of instructor support on engagement via interaction. This study is among the first SEM-based investigations in Vietnamese medical education that quantifies both direct and mediated effects of instructor support on cognitive engagement via classroom interaction. To examine the associations among pedagogical learning environment, instructor support, classroom interaction, and cognitive engagement in medical students, and to test classroom interaction as a mediator. MATERIALS AND METHODS: In 2025, a cross-sectional descriptive study surveyed 434 fourth-year medical students (51.2% female; 22.15 ± 0.89 years) at Can Tho University of Medicine and Pharmacy, Vietnam. Classroom interaction, instructor support, and cognitive engagement were measured using validated, context-adapted scales comprising 39 Likert items: Situational Cognitive Engagement Questionnaire (4; H = 0.88), UWES-S (9), USEI (15), and 6 instructor-support items. Internal consistency was excellent (Cronbach’s α = 0.798–0.943). SEM was conducted using IBM SPSS AMOS 26.0; P < 0.05 (two-tailed tests). RESULTS: The SEM demonstrated acceptable-to-good model fit ( χ ²/df = 2.717; CFI = 0.893; TLI = 0.880; RMSEA = 0.063; SRMR = 0.040). All three hypotheses were supported: (1) instructor support positively predicted classroom interaction ( B = 0.631, P < 0.001); (2) classroom interaction positively predicted cognitive engagement ( B = 1.421, P < 0.001); and (3) classroom interaction partially mediated the effect of instructor support on cognitive engagement ( B = 0.897), accounting for 43.1% of the total effect. The direct effect of instructor support on cognitive engagement remained significant ( B = 1.184, P < 0.001), indicating dual pathways. CONCLUSION: Instructor support influenced cognitive engagement both directly (56.9%) and indirectly via classroom interaction (43.1%), supporting a complementary “both-and” model. Medical schools should invest in faculty development to strengthen autonomy-supportive teaching while redesigning learning activities to create structured interaction opportunities. Optimizing engagement likely requires simultaneous reinforcement of both instructional support and interactive classroom conditions.
Hong et al. (Wed,) studied this question.