Effects of a classroom discourse intervention on teachers' practice and students' motivation to learn mathematics and science

• TPD on productive classroom discourse has positive effects on students' interest.
• Reflection-based TPD promotes productive teacher discourse practices.
• Changes in students' situational motivation predict changes in interest during TPD.

Student interest and motivation in STEM subjects has dropped significantly throughout secondary education, for which teacher–student interactions are named as a central reason. This study investigated whether a video-based teacher professional development (TPD) intervention on productive classroom discourse improved students' learning motivation and interest development over the course of a school year. The teachers' intervention group (IG; n = 6) was compared with a control group (CG; n = 4) who participated in a traditional TPD programme on classroom discourse. The teachers showed a significant increase in constructive feedback and decrease in simple feedback as a function of the treatment. Pre- and post-tests revealed that students in the IG (n = 136) significantly increased their perceived autonomy, competence and intrinsic learning motivation as compared with those in the CG (n = 90). They also showed significantly greater interest changes in the subjects compared with their peers in the CG.