How important is Progress 8 in schools?

[TwoMountains]

We’re looking at secondary school preferences for DC1.

I’ve come across mention of something called Progress 8 when researching our nearest schools.

School 1 (nearest) has a Progress 8 score of 0.22 (average).
School 2 (2nd nearest) has a Progress 8 score of -0.45 (below average).
No Progress 8 data available for School 3 (3rd nearest).
Based on 2019 data.

Thing is, I don’t really understand what Progress 8 means and how important a thing it is to consider when looking at schools.
Can anyone explain please?

It's a way of making sure pupils progress stays on track. Eg pupils with the top stats scores going from primary to secondary suddenly coming out with rubbish grades.

Following with interest. Also attainment 8.

It tells you how much progress on average the students make from KS2 to KS4. If they make expected progress, the school will have a score of zero. Below zero is less than expected and above means students made more progress than expected. Most schools tend to be close to zero. I would say any school with a score below -0.3 would consider itself well and truly in the shit and about to be handed their arse on a plate by Ofsted unless they could demonstrate that it was a blip. And that’s worth looking at - P8 scores over time. Also, not all pupils count - they only count if they sat KS2 tests, so schools with lots of students with SEN might do badly as those students might not count in the figures.

Attainment 8 is just best grades, so grammar schools will do way better than comps because they are selective.

Progress 8 looks at progress. You can look at progress 8 for previous low, average and high attainers. (English & Maths are double scored, then you have to have some specific things in buckets, and then some 'free' ones).
Progress can be impacted by whether the feeder primaries go all out for SATs or have a more rounded approach.

Remember in some areas less good schools can be bolstered by private tutoring.

@Autumngoldleaf

It's a way of making sure pupils progress stays on track. Eg pupils with the top stats scores going from primary to secondary suddenly coming out with rubbish grades.

So… I assume a positive number is good and a negative number bad?

As in a negative Progress 8 score means pupils are doing worse at GCSE than you’d expect based on SATs?

How far away from zero does a Progress 8 score have to get before it’s considered significantly bad (or good)?

Cross posted, I see some of my questions are already answered!

I think, but happy to be corrected that Progress of +0.5 would mean on average the students would score half a grade better than would be expected.
So that means e.g. instead of 5555 5555 they would get 5555 6666.
This is all measured on a cohort and doesn't really say masses about how your own DC will do in 5/6 years time.

I found a local news article about School 2’s performance in 2018.

Progress 8 scores in 2018 were about -0.6, so I guess at least they improved between 2018 and 2019.