Why Performance Data Matters (and Its Limitations)
Performance data gives you a snapshot of how well a school is educating its pupils — but it's only one piece of the puzzle. Think of it like a financial statement for a company: it tells you important things, but it doesn't capture culture, values, or the experience of being there.
That said, understanding the data helps you:
- Identify schools that consistently help pupils make strong progress
- Spot potential concerns (e.g. declining results, low attendance)
- Compare schools on a level playing field
- Ask better questions when you visit schools
Primary School Data (KS2)
1. Attainment: Percentage at Expected Standard
This tells you what proportion of Year 6 pupils reached the expected standard in reading, writing, and maths. The national average is typically around 60-65% for all three combined.
- Above average: The school is getting more children to the expected standard than most schools
- Below average: Fewer children are reaching expected standard — but this needs context (see Progress below)
2. Attainment: Percentage at Higher Standard
This shows how many pupils exceeded the expected standard, indicating how well the school stretches its highest-achieving pupils.
3. Progress Scores — The Most Important Measure
This is where the data gets really meaningful. Progress scores measure how much progress pupils make from the end of Key Stage 1 (Year 2) to the end of Key Stage 2 (Year 6), compared to pupils nationally who had similar starting points.
- A score of 0 means pupils made average progress
- A positive score (e.g. +2.1) means pupils made more progress than average — the school is adding value
- A negative score (e.g. -1.5) means pupils made less progress than average
Why this matters: A school in a disadvantaged area might have lower attainment but excellent progress scores. This means the school is doing a brilliant job of helping pupils learn, even if their starting points were lower. Conversely, a school in an affluent area might have high attainment but average progress — meaning the results have more to do with the children's backgrounds than the school's teaching.
4. Confidence Intervals
Each progress score comes with a confidence interval — a range that shows how statistically significant the score is. If the confidence interval includes zero, the score isn't significantly different from average. Small schools tend to have wider confidence intervals because individual pupils have a bigger impact on the average.
Secondary School Data (GCSEs)
1. Attainment 8
This measures the average GCSE grade across 8 subjects. A score of roughly 46-48 indicates average attainment. The subjects include:
- English (double-weighted)
- Maths (double-weighted)
- Three EBacc subjects (sciences, languages, humanities)
- Three other qualifying subjects
2. Progress 8
Like KS2 progress scores, this measures how much progress pupils make from the end of KS2 to their GCSEs, compared to pupils nationally with similar starting points.
- 0 = average progress
- Positive = pupils make more progress than expected
- Negative = pupils make less progress than expected
A Progress 8 score of +0.5 means pupils achieve, on average, half a grade higher in each subject than similar pupils nationally. That's significant.
3. Percentage Entering EBacc
The EBacc (English Baccalaureate) is a group of subjects considered academically rigorous: English, maths, science, a language, and history or geography. There's no separate qualification — it's a measure of curriculum breadth.
A high EBacc entry rate suggests the school offers a broad, academic curriculum and encourages pupils to take a range of subjects.
4. Staying in Education or Employment
This measures what happens to pupils after they leave the school. A high percentage staying in education or training suggests the school prepares pupils well for their next steps.
What the Data Doesn't Tell You
School Culture and Ethos
Numbers can't capture whether a school feels warm and welcoming, whether children are happy, or whether the staff genuinely care.
SEND Provision
Performance data doesn't tell you how well a school supports children with special educational needs. A school with excellent SEND provision might have lower headline figures precisely because it welcomes and includes children who find learning more challenging.
Enrichment and Extra-Curriculars
Music, sport, drama, clubs, trips — none of this appears in the performance data, yet it can be a huge part of what makes a school special.
Context
A school serving a community with high deprivation, high mobility (pupils joining and leaving), and high proportions of children with EAL (English as an Additional Language) faces very different challenges to a school in a stable, affluent area.
How to Use the What School
On the What School, we present performance data alongside:
- The school's context (FSM percentage, deprivation index)
- Enrichment activities and clubs
- Staff stability
- Attendance rates
- Ofsted report card assessments
- SEN provision data
This gives you a much more rounded picture than any single data source.
Useful Resources
- School performance tables (GOV.UK)
- Understanding school data (DfE guide)
- Explore school profiles on the What School for an integrated data view
Data is a tool, not a verdict. Use it to narrow your choices and sharpen your questions — but never let a number override your instincts about where your child will be happiest.