The Mediating Effect of Teaching Competence on the Relationship Between Differentiated Instruction and Academic Achievement of Diverse Learners

This study examined the mediating effect of teaching competence on the relationship between differentiated instruction and academic achievement among diverse learners at Kiamba National High School, Sarangani Province, Philippines. Specifically, it determined the levels of teaching competence, differentiated instruction, and academic achievement; examined the relationships among these variables; and investigated whether teaching competence significantly mediated the effect of differentiated instruction on students' academic achievement. A quantitative descriptive–correlational research design with mediation analysis was employed. The respondents consisted of Senior High School students selected through stratified random sampling with proportional allocation. Data were collected using adapted and validated standardized questionnaires measuring differentiated instruction, teaching competence, and academic achievement. Descriptive statistics, Pearson's product-moment correlation, and regression-based mediation analysis were utilized to analyze the data at a 0.05 level of significance. Results revealed that teachers demonstrated a very high level of teaching competence, while differentiated instruction was consistently implemented, particularly through learning stations, scaffolding instruction, learning contracts, and anchor activities. Learners likewise exhibited a very high level of academic achievement. Correlation analysis indicated significant positive relationships among differentiated instruction, teaching competence, and academic achievement. Mediation analysis further established that teaching competence significantly and partially mediated the relationship between differentiated instruction and academic achievement, indicating that differentiated instructional practices improve learner performance both directly and indirectly through enhanced teacher competence. These findings underscore the critical role of competent teachers in maximizing the effectiveness of differentiated instruction and suggest that continuous professional development and strengthened instructional practices are essential for promoting inclusive, equitable, and high-quality learning outcomes among diverse learners in Philippine secondary schools.