Schools with the most effective headteachers see pupil progress boosted by an extra grade in two GCSE subjects, a landmark new study has found.
Research by the Education Policy Institute also found that more experienced leaders and those who stayed in the same school for several years saw a larger boost in pupil outcomes.
The study used national data on all pupils and heads in England between 2004 and 2019 to follow 22,300 primary and 5,400 secondary headteachers and track their impact on metrics like pupil progress, teacher turnover and teacher absences.
