This study investigates if INOVASI's Guru BAIK pilot, an adapted Classroom Action Research approach, works to improve teacher competencies to deliver quality learning and if the improvements generate better learning outcomes. The pilot aims to enable teachers to develop their teaching competency by helping teachers develop a willingness to learn, and to become aspirational, inclusive and contextual in administering their teaching and learning process. We investigate the performance by comparing baseline and endline results of the pilots in Sumbawa and Southwest Sumba. The end-line study results show that Guru BAIK has increased the students' literacy and numeracy skills. The findings also demonstrate that it works better for less advantaged children, for instance due to gender and student's socioeconomic background. These positive outcomes may have been generated by better teaching practices. The teachers shifted their teaching practices to be more student-centered; they applied active learning, used learning media, improved the degree of student engagement, diversified types of student assignments, and reduced teacher absenteeism. To conclude, the adjusted CAR drives changes for teachers' mindset and practices and was proven to improve learning outcomes. Nonetheless, technical inputs are still required to sustain the results, in particular at higher grades.