Every May, around 600,000 ten and eleven year olds in England sit a week of national curriculum tests, and every July their families receive a set of numbers that many read as a verdict on the child. That reading gets the purpose backwards. Key stage 2 SATs were designed, and are still run, as an audit of schools. The child is the measuring instrument, not the thing being measured.
The machinery makes this plain. The tests are written and administered by the Standards and Testing Agency, an executive agency of the Department for Education, and sat under exam conditions in a single week of May: an English reading paper, two grammar, punctuation and spelling papers, and three mathematics papers — one arithmetic, two reasoning. All six are sent away for external marking. Writing is the exception: it is assessed by the child's own teachers against national frameworks across the year, with local authorities moderating a sample of schools to keep judgements honest. A science sample runs in selected years in a small subset of schools, purely to monitor national standards, and most pupils never sit it.
Raw marks are converted into scaled scores running from 80 to 120, where 100 represents the expected standard and 110 or above counts as the higher standard. The conversion table is rebuilt each year, because the papers vary in difficulty and the scale, not the raw mark, is meant to stay constant. In a typical year roughly six in ten pupils reach the expected standard in reading, writing and maths combined, which means a large minority of perfectly capable children fall short of a threshold that was never calibrated as a personal pass mark.
What the scores actually feed is the accountability apparatus. School-level results appear in the DfE's performance tables, where parents, governors and journalists compare attainment and, more importantly, progress — the value a school added between key stage 1 starting points and key stage 2 outcomes. Ofsted inspectors use the same data to decide which schools warrant early inspection and to frame the questions they ask when they arrive. A sustained dip in SATs outcomes can trigger intervention, leadership change or forced academisation. That is the pressure that leaks into Year 6 classrooms as booster groups, practice papers and breakfast revision clubs, and then into children as nerves.
What the numbers mean for an individual child
Rather less than the anxiety implies. No secondary school admission in England depends on SATs; grammar school entry runs on entirely separate 11-plus tests set by councils or school groups months earlier. Most secondaries re-test their intake in the autumn of Year 7 anyway, commonly with cognitive ability tests, precisely because they trust a fresh measure more than a score produced under heavy preparation. The one lasting statistical use is invisible to the child: KS2 results form the baseline for Progress 8, the measure by which the secondary school will itself be judged on GCSE results five years later. A child's SATs score follows them as a yardstick for their next school, not as a label on them.
A scaled score of 97 does not mean a child cannot read or reason; it means that on one week's papers they finished a few marks below a cut-off drawn for institutional comparison. Teachers know this, which is why end-of-year reports lean on teacher assessment and classroom evidence rather than the July printout.
Why the tests persist anyway
Governments keep SATs because the alternative is flying blind. Before national testing, there was no consistent evidence on whether primary schools in Sunderland and Surrey were teaching to comparable standards, and disadvantaged pupils' underachievement could stay statistically invisible. Universal external tests, whatever their side effects, produce a comparable national dataset — the reason key stage 1 SATs, which became non-statutory in 2023, were retired only once the Reception baseline assessment could anchor progress measures instead.
The honest summary for a Year 6 parent runs like this: the tests matter a great deal to the school, moderately to the government, and marginally to the child. Preparation that keeps a pupil calm and fluent is worth having; preparation that convinces a ten year old their future turns on a scaled score is measuring the wrong thing entirely.