Scaled scores, and why 100 is the number that matters

At the end of Year 6, children sit their KS2 SATS, and the results don't come back as a mark out of forty or a friendly percentage. They come back as a "scaled score", which is one of those phrases that sounds more complicated than it is.

Let me unpick it, because it's worth understanding before the results land.

Why not just use the raw mark?

Every year's papers are slightly different. One year's reading paper might be a touch harder than the last. If schools just used raw marks, a 35 out of 50 in a hard year would look worse than a 35 in an easy year, even though the child did better. That isn't fair, so the raw marks get converted onto a fixed scale that means the same thing every year.

That scale runs from 80 at the bottom to 120 at the top. And the number in the middle of all the fuss is 100.

100 is the expected standard

A scaled score of 100 means a child is working "at the expected standard" for the end of primary school. Below 100, they haven't quite got there yet. Above it, they're ahead. So 100 is the line, and you'll hear teachers and parents talk about being "above 100" or "below 100" as shorthand for whether a child is where they're meant to be.

It's worth saying that 99 and 101 are not different worlds. A point either side of the line is a hair's breadth, not a cliff edge. The number is useful as a rough position, not a label to hang round a child's neck.

What a "good" score looks like

100 is the standard. Around 110 and above is usually described as working at a higher standard, sometimes called greater depth. The very top of the scale, 120, is rare and means very nearly full marks on a hard paper. Most children land somewhere in the broad middle, and that is completely fine. The scale is built so that "expected" is genuinely the expectation, not an aspiration.

Why we use it before Year 6

We run a monthly benchmark in our house that copies the SATS style and produces a scaled score the same way. Not because a nine-year-old needs to be revising for SATS, they really don't, but because one number tracked over time tells you something a single test never can. A child who goes 96, 98, 101, 103 across a term is on a lovely trajectory, and you can relax. A child drifting the other way is worth a gentle look now, while there's still loads of time to do something about it.

That's the real value of the scaled score. Not the number itself on any given day, but the direction it's heading. Watch the trend, not the dot.