A randomized controlled trial of the effectiveness of teacher continued professional development on student language outcomes.

What is already known on this subject Although inconclusive, previous research indicates that intervention delivered to teachers by SLTs has the potential to improve the language abilities of the students in the teachers' classrooms. What this paper adds to existing knowledge This study explored the language development of first- and second-year mainstream school students whose teachers took part in a CPD programme aimed at establishing language and communication-supporting teaching techniques. Results indicate that the development of the students' language abilities could not be attributed to the teachers' participation in the CPD. What are the potential or actual implications of the work? SLTs are often asked to guide teachers and teaching staff rather than themselves conduct individual assessments and interventions. The results of this trial can be used to inform the discussion on how to prioritize between tasks.