Does instructional leadership drive educational improvement in South Africa? Evidence from Oaxaca-Blinder decomposition analysis

Quality school leadership and management are important determinants of teaching and learning quality. According to South Africa's National Development Plan (NDP), principals should provide administrative and curriculum leadership to schools. This study investigated the improvement between 2015 and 2019 Grade 9 mathematics scores in South Africa, and explored the extent to which the difference could be related to instructional leadership. Using the Oaxaca-Blinder (OB) decomposition technique, the performance gap is decomposed into a part that is associated with changes in the number of educational inputs, such as student, teacher, and school/principal characteristics, and a part that is associated with changes in the efficiency of the educational inputs. The findings suggest that instructional leadership variables are positively associated with increased mathematics scores but the return to student achievement was lower in 2019 than 2015. The findings also revealed that instructional leadership led to less improvements among under-resourced schools in 2019.