Professional Learning Communities and Mathematics Achievement: Empirical Evidence of a Sequential Multi-Path Mediation Model

Mathematics achievement in Indonesian maritime vocational higher education remains a persistent challenge. Teachers in these institutions commonly work in isolation, which limits the consistency and quality of mathematics instruction. This study examines how Professional Learning Communities (PLCs) improve student mathematics achievement through three mediating pathways: Cognitive Activation in Lessons (CAL), Collective Teacher Efficacy (CTE), and Differentiated Instruction (DI). A quantitative cross-sectional design was applied to 674 students at Politeknik Ilmu Pelayaran Semarang during the 2025 academic year, representing 85% of the eligible student population. Five constructs were measured using validated psychometric instruments: PLCs, CTE, CAL, DI, and Student Achievement in Mathematics (SAM). Structural Equation Modeling (SEM) with bias-corrected bootstrapping tested all proposed mediation pathways. Three significant mediation pathways were confirmed. PLCs improved mathematics achievement directly through cognitive activation in lessons. PLCs also strengthened collective teacher efficacy, which subsequently enhanced cognitive activation and student outcomes. PLCs further built collective teacher efficacy, which enabled differentiated instruction and produced the strongest effect on mathematics achievement. PLCs generated the largest total effect on student achievement across all pathways. The findings extend Bandura’s social cognitive theory and Pekrun’s control-value theory of achievement to a non-Western vocational education setting. Results offer an evidence-based framework for educational leaders aiming to strengthen mathematics competency in technical and vocational institutions aligned with Industry 4.0 demands.