Teacher Quality and Student Learning in K–12 Education: A Systematic Review

<title>Abstract</title> <p>Teacher quality is widely recognized as an important factor in improving student learning; however, the construct is multidimensional and has been defined and measured differently across educational research. This systematic review synthesized empirical research on teacher quality and student achievement in K–12 education published between 2005 and 2026. The review examined how teacher quality was conceptualized and the dimensions or indicators used to represent it, as well as what empirical evidence revealed about its relationship with student achievement. Following a systematic process of literature identification, screening, eligibility assessment, and selection, 32 studies were included and analyzed using narrative and thematic synthesis. The findings showed that teacher quality was conceptualized through several interrelated dimensions, including teacher qualifications and certification, teaching experience, subject-matter and pedagogical content knowledge, professional training and development, instructional quality and classroom practices, and demonstrated teacher effectiveness. Overall, teacher quality was positively associated with student achievement, although the strength and consistency of the relationship varied across indicators and educational contexts. Formal qualifications and certification showed mixed relationships with achievement, while teaching experience was generally beneficial, particularly during the early years of teachers’ careers. Teacher subject-matter knowledge, pedagogical content knowledge, instructional quality, and demonstrated effectiveness showed more consistent positive relationships with student achievement. The findings suggest that teacher quality is best understood as a multidimensional construct extending from teachers’ preparation and professional characteristics to their knowledge, instructional practices, and contributions to student learning. The review highlights the importance of moving beyond reliance on formal credentials alone when developing policies and practices intended to strengthen teacher quality and improve student achievement.</p>