The process of Action Research involves careful, well-reasoned planning, action, observation, and reflection by the teacher. This process, which originated in Europe, is now a professional tool for teacher transformation through perspective thinking based on retrospective reflection on the "regulation" of teaching and learning in the classroom, which strengthens teacher’s professionalism. Therefore, the problem was solved using the stages of Action Research. Grade 9 was the focus of the study and our goal was to help students develop analytical skills. To do this, there was applied the principle of "deepening" of differentiation in this study. As a result, the interest and activity of the class, the "manifestation" of students' creativity, as well as "progress", a significant increase in the quality of classroom learning were observed. We found that taking into account the "voice of the student" contributes to effective reflection and professional development. This demonstrates the effectiveness of using Action Research.