When looking at the grade achieved across all three cohorts, we used a Welch’ s t-test to compare the means of two independent groups( e. g. Year 10s vs Year 11, Male vs Females) as it doesn’ t require equal grouping and as we have 29 students in Year 10 and 14 students in Year 11, the Welch’ s t-test adjusts for this.
Year 10 vs Year 11— key differences
1) GCSE outcomes:
• Year 10 average GCSE ≈ 4.07 vs Year 11 ≈ 2.67; difference is statistically significant( Welch’ s t ≈ 4.04, p ≈ 0.00086), large effect( Cohen’ s d ≈ 1.54).
2) Pre → Post assessment gains:
• Year 10 mean gain ≈ + 1.71 vs Year 11 ≈ + 1.09; significant( t ≈ 2.22, p ≈ 0.036), moderate – large effect( d ≈ 0.78).( Note: some“ pre” values are missing where“ not completed”; analysis uses available cases.)
3) Residuals( value-add):
• GCSE – assessment residuals: Year 10 ≈ + 0.55, Year 11 ≈ + 0.58 → no meaningful difference( p ≈ 0.91).
• GCSE – mock residuals: Year 10 ≈ + 0.76, Year 11 ≈ + 0.67 → no significant difference( p ≈ 0.76).
• Interpretation: Year 10 students achieved higher GCSE grades and larger gains between pre and post assessments, but the added value relative to assessments / mocks looks similar across years. Because Year 11 is English Language only, while Year 10 includes Maths, part of the GCSE difference may reflect subject mix and cohort baseline differences. Even within English Language, Year 10’ s mean GCSE( ≈4.14) is higher than Year 11’ s( ≈2.67), so the cross-year difference isn’ t solely due to Maths.
Attendance— does it relate to results?
• Overall( all students): o Attendance vs GCSE: r ≈ + 0.03( Pearson), near zero— no meaningful association. o Attendance vs residuals( assessment / mock): ≈0 to −0.15— no clear pattern. o Attendance vs pre → post gain: r ≈ −0.25( Pearson), −0.23( Spearman): a small negative association, possibly reflecting ceiling effects( students already strong at pre have less room to“ gain”) and / or mixed attendance scales.
• By year: o Year 10: Attendance shows a small positive correlation with GCSE( r ≈ + 0.26) and a small negative with gain( r ≈ −0.28). Residuals ~ 0.10 or less. o Year 11: Correlations are near zero to slightly negative( n is small).
• By subject: o Year 10 English Language: Attendance vs GCSE r ≈ + 0.38( n = 14). o Year 10 Maths: Attendance vs GCSE r ≈ + 0.24; vs GCSE – mock residual r ≈ + 0.44( n = 7, interpret cautiously). o Year 11 English Language: Correlations slightly negative( r ≈ −0.19 GCSE; −0.16 residual), but under-powered.
Higher attendance mildly aligns with better GCSE in Year 10( especially English Language), but relationships are small and not consistent in Year 11. Therefore, this is inconclusive and would need to be replicated in further cohorts.
Page 9 of 22