Which in-Service Training Best Facilitates the Professional Growth of Beginning Teachers? An Empirical Study Based on Primary and Secondary School Teachers in Shanghai

This study, based on a questionnaire survey of 1,512 newly appointed teachers in Shanghai's compulsory education sector, aims to explore the impact of different types of in-service training on their professional competence development. Teacher professional competence was categorized into four dimensions: professional attitude, teaching practice, comprehensive education, and autonomous development. We examined the relationship between training content, format, learning methods, and mentor guidance with each dimension of professional competence. Findings indicate: (1) Training content exerts targeted effects, with three categories—professional ethics, classroom work and moral education practice, and educational research—significantly enhancing autonomous development, teaching practice, and professional attitude respectively; (2) Mentor guidance proves the most critical factor in elevating professional competence, substantially amplifying the efficacy of most training content; (3) Training format and learning methods exert limited influence; (4) Teachers’ individual characteristics (such as gender, educational background, and internship environment) exert a moderating effect on training outcomes. Based on these findings, this study constructs and proposes a ‘mentor-led, practice-research oriented’ in-service training model centred on ‘mentor guidance’ and keyed to ‘practice-based research’, providing empirical evidence and practical pathways for optimizing the support system for beginning teachers.