A school with 80% KS2 attainment sounds better than one with 65%. But progress scores tell a completely different story — and they're what really matters.
Every autumn, primary schools across London publish their Key Stage 2 results. Parents pore over the percentage of pupils who met the expected standard in Reading, Writing and Maths. Schools with higher percentages are assumed to be better schools.
This assumption is often wrong.
Attainment is the percentage of Year 6 pupils who achieved the expected standard (or higher) in the national tests. The national average is approximately 60-65% for Reading, Writing and Maths combined.
Progress measures something different: how much did pupils improve from the end of Key Stage 1 (age 7) to the end of Key Stage 2 (age 11), compared to pupils nationally who started at the same level?
A progress score of 0 means pupils progressed exactly as much as the national average for children with similar starting points. A score of +2 means pupils progressed significantly more than expected. A score of -3 means pupils fell behind peers with similar starting points.
Consider two London primary schools:
School A has 78% of pupils meeting the expected KS2 standard. It serves a largely affluent neighbourhood with few pupils eligible for Free School Meals. Its progress score is -1.2 — pupils are actually progressing slightly below the national average for children at their starting level.
School B has 61% of pupils meeting the expected KS2 standard. It serves a high-deprivation community with 45% of pupils on Free School Meals. Its progress score is +3.1 — pupils are progressing well above the national average for children at their starting level.
Which school is doing a better job of educating its pupils? By any meaningful measure, School B — but the headline attainment figure tells the opposite story.
Free School Meals eligibility (FSM%) is the standard proxy for socioeconomic disadvantage in UK school data. Schools serving high-FSM communities almost always show lower attainment scores than schools serving affluent communities — not because they are worse schools, but because pupils arrive with different starting points and face different challenges outside school.
This is why progress scores exist. They attempt to strip out the effect of starting point and socioeconomic background, leaving a purer measure of teaching quality.
Single-year KS2 data can be misleading. A cohort of 30 Year 6 pupils contains enormous natural variation. One unusually strong or weak cohort can swing a school's attainment figure by 8-10 percentage points.
The three-year rolling average smooths this out. Where available on ofsted.london, this figure gives a more stable and reliable picture of a school's typical performance over time.
The most complete picture comes from reading attainment, progress and context together:
Progress scores are available on ofsted.london for all primary schools that reported KS2 data. Filter by borough, then look at both the attainment percentage and the progress score together. The combination tells you far more than either figure alone.
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