The Effect of Professional Development-Supported Instructional Practices on Students' Algebra Achievement

This study employed a quasi-experimental design to investigate the effect of instructional practices supported by professional development (PD) training on the development of algebraic thinking skills among 7th-grade students. Twenty middle school mathematics teachers received PD training focused on fostering algebraic habits of mind (AHoM). The experimental group comprised 7th-grade classes taught by trained teachers, while the control group consisted of classes taught by teachers who followed the traditional curriculum and did not participate in the training. The intervention was implemented over a 10-week algebra unit, during which AHoM-focused instructional practices were applied in the experimental classrooms. The Algebra Knowledge Test was administered as both a pre-test and post-test. Student responses were scored quantitatively (sufficient solution: 3, developable solution: 2, non-evidentiary solution:1) and analyzed using statistical methods. While no significant difference was observed between groups at baseline (p = .224), post-test results revealed a statistically significant advantage in favor of the experimental group (p .001, Cohen’s d = 0.36), indicating a small-to-moderate educational effect. These findings suggest that PD training aimed at cultivating algebraic thinking habits contributes meaningfully to students’ algebra achievement. It is therefore recommended that PD programs emphasizing algebraic habits of mind should be systematically integrated into mathematics education practices to enhance students’ algebraic proficiency.