Although teaching reflection diaries (TRDs) are prevalent tools for teacher training, TRDs are rarely used in Japanese secondary educational settings. In order to delve into the effects of TRDs on teaching development, this illustrative case study was conducted with two female teachers (one novice, and one experienced) at a Japanese private senior high school. The research findings demonstrated that both in-service teachers perceived TRDs as beneficial tools for understanding their strengths and weaknesses. TRDs and class observations illustrated that the novice teacher raised their self-confidence in teaching and gradually changed their teaching activities. On the other hand, the experienced teacher held firm teaching beliefs based on their successful teaching experiences and were sometimes less willing to experiment with different approaches. However, they changed their teaching approaches when they lost balance between their class preparation and other duties. Accordingly, although teachers’ firm beliefs and successful experiences may sometimes become possible hindrances from using TRDs effectively, TRDs can be useful tools to train and help teachers realise their strengths and weaknesses.
A longitudinal case study of six children with autism and specified language and non-verbal profiles