Middle school preservice mathematics teachers' in-class mathematical modeling practices in the context of adapted lesson study

In this study, it was aimed to examine the changes in the instruction dimension, which is one of the teacher competencies in mathematical modelling teaching, of middle school preservice mathematics teachers who participated in the adapted lesson study professional development model. The research model of the study, which was conducted in the spring semester of the 2022-2023 academic year, is a case study. The study group of this research consisted of six preservice mathematics teachers. The research, which was completed in 14 weeks, was carried out in two dimensions: theoretical education and practice, based on the adapted lesson study professional development model. The data of this study were collected through audio and video recordings of the planning, implementation and reflection steps in each implementation, semi-structured interviews and audio recordings of interviews conducted during the planning and reflection stages, implementation plans, observation notes and reflection reports. The data obtained were analysed using qualitative data analysis methods. It is seen that there are many positive changes in preservice teachers' planning of the implementation. In addition, it was determined that there were mistakes, deficiencies and aspects that needed to be improved in their conducting of the implementation and their interventions, support and feedback in this process. On the other hand, it was concluded that the adapted lesson study professional development program made significant contributions to preservice teachers in the instruction dimension and that the preservice teachers who participated in this professional development program were able to improve in many areas.