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Case Study - Tiffin School Physics department

The chart below shows the % grades awarded A* to B in the past 5 years of A-level results for Tiffin School Physics department.
Teachometer was introduced to the new Year 12 cohort in September 2017. The cohort comprised of 76 students. Teachometer was used in all lessons as well as for fortnightly assessments. No members of staff joined or left the department over this period.
Just under two years later from the June 2019 A-level results, the % grades awarded A* to B improved by 8.0%. When compared to the trend this is clearly more than just a statistical fluctuation.