How to research secondary schools performance?

[SureWould]

Didn't grow up in UK so forgive my ignorance.

Ds1 is middle set. Dd2 is top set. Both state primary. Can afford private but rather grammar/good comp if possible. We will have to move house at some point, when there's more schools visibility.

Looking at DOE tables at GCSE English and Maths results for non-selective comps. Quite a few suffer a precipitous drop at A Level (I look at %AAB in 3 facilitating subjects). Is that because in those schools the best performers always leave to a grammar /private for 6th form? Or worst get kicked out to do Btechs?

I know schools are much, much more than league tables but looking for statistical markers for how well it does academically.

Attainment 8 looks at 'best 8' GCSEs but maths is double weighted, English takes the best of the 2 provided both are taken, and there are 'bucket' rules such as there has to be a science and stuff like that (to ensure a broad academic approach). There are similar rules for Progress8. Or something. Details might not be quite right.

I like the sound of attainment 8!

Attainment 8 doesn't really tell you loads about how well the school teaches though. It can say more about the intake than the teaching. e.g. You would expect grammars to have far better attainment 8 than comps.

I think 2022 provisional results should be up soon. It's hard to judge based on 2019 as the schools may have changed dramatically (in either direction).

Non-selective state schools won't report A*-B (which is probably 9-6 in current money).

Bear in mind that your average state school takes a range of ability, which is why others are suggesting that progress is more interesting than attainment (you need to choose the "show all data option" to see this split by high/medium/lower achievers).
Or, put another way, a selective school probably only takes in children that are likely to get mostly As. If they end up with mostly As that shows the school is simply doing what it should. A non-selective state school will take in a huge range of abilities, including some children for whom (e.g) a C might be major achievement. The fact that the non-selective school doesn't end up with huge swathes of DC on high grades doesn't really show anything. You need to consider intake, not just results.

Too early to look at A Levels. Many students change schools at sixth form anyway.

I can see a couple like this on my list with big consistently negative progress 8 score and would definitely want to avoid them.

The problem with taking such a rigid view is that you'll miss the school which got a new head and senior management team last year, who have instigated huge changes that have had a massive impact on the school and that the younger years will massively benefit from.

Because it’s not about how the pupils perform in line with expectations, it’s how they perform in comparison to the rest of the national cohort. A P8 score of +1 (which is very rare) means that the pupils performed on average a full grade higher than comparable students in the same year. If the whole national cohort underachieved in terms of expected progress an individual school could still get a positive P8 by outperforming other schools.

Hit post too soon - this is why P8 isn’t published until late into the autumn term, once the summer data has been processed.