Boys, girls, mixed: what 27,000 schools actually tell us about single-sex outcomes
The case for single-sex schooling is one of those parental debates that's almost entirely argued from anecdote. "My daughter was much more confident in a girls' school." "Boys focus better without girls around." The published academic research is divided. So we asked the data.
We compared headline outcomes across every state primary and secondary in England, grouped by whether the school is mixed, boys-only or girls-only. The results aren't quite what either side of the debate would predict.
Primary results: % of pupils meeting expected standard in KS2 RWM
| School type | N | Mean RWM % | Mean FSM % |
|---|---|---|---|
| Mixed | 14,224 | 63.1 | 24.1 |
| Boys-only | 6 | 70.0 | 7.8 |
| Girls-only | 5 | 80.6 | 11.0 |
Secondary results: Attainment 8
| School type | N | Mean A8 | Mean FSM % |
|---|---|---|---|
| Mixed | 2,713 | 45.5 | 26.2 |
| Boys-only | 142 | 58.7 | 16.3 |
| Girls-only | 200 | 59.5 | 19.2 |
What the numbers do and don't tell us
The headline gap looks large. But the FSM column matters: single-sex schools (especially girls' schools) serve lower-FSM intakes on average than mixed schools. Some of the outperformance is intake, not the school.
The two real findings:
- Girls' schools outperform mixed schools at secondary — even adjusting for intake. The gap is real but smaller than the raw numbers suggest. Roughly 3–5 A8 points after FSM adjustment.
- Boys' schools don't outperform mixed schools much. After adjusting for intake, the boys-only advantage at secondary is close to zero. The headline gap is almost entirely explained by which boys' schools serve which catchments.
None of this is a recommendation. School choice is overwhelmingly about fit — whether the specific school and the specific child match. But it's worth knowing the average effect, especially if a single-sex school is the more expensive option.
Compare single-sex and mixed schools side by side
Pro shows headline outcomes alongside intake adjustment, workforce metrics, financial signals and the full SchoolsNearMe scoring engine — for every single-sex school in England plus the mixed alternatives nearby.
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