Headline GCSE stats....

I was thinking more that if a school was well below average (around the bottom 10%?) it would be scrutinized and expected to improve (or valid reasons for its underperformance accepted). So yes, you'd want to look at their following years results to ensure they had improved, but as long as they had you should be happy.
I'd be unconcerned about schools average or above, as they are serving their pupils around as well or better than the national average and within that there's almost bound to be movement - I would have thought it's unlikely that the same schools would stay at the top (except for selective schools possibly) as it's unlikely that all the teaching goes right and no problems in the cohort year on year, though I guess in a really well managed school it might. There's possibly a case to monitor below average schools too, but half the schools will always have scores lower than zero, rather fewer with the actual category ' 'below average', so it kind of depends whether you consider the acceptable range to encompass the below average category or not. They tend to have scores between around .25 and half a grade lower than average, so the question is if that's an acceptable spread or not. If it is look at them if not don't.
At that kind of level of granularity exact year on year comparisons aren't especially useful.

The point is, if you want to use data to intelligently compare schools - and to see what is working (are the children there making better progress, or not) and what is not - you absolutely need reliable time series.

Just as an example, a school I know of was below average in last year's dataset, and average this year. If I knew that the data was comparable, i could ask reasonably insightful questions about what they had changed, whether they were simply very different cohorts or whether they had adjusted teaching practice to ensure better progress etc. However, as the basis of comparison has changed, I can only say that it is probably because they are a selective school and therefore more of their progress was between A and A* than between E and D - it potentially tells me nothing about the school itself.

Don't really see the point of comparing year on year anyway.
Sorry?
What ?
Time series data are some of the most powerful sets as they are what show the development and impact of changing situations and policies
(eg the removal of lead from fuel significantly improving city school results)

Don't really see the point of comparing year on year anyway. As you rightly said before the 5 broad bands are about as much granularity as you need (you might get away with deciles,but no more than that)

So this year's Progress8 is not comparable to last year's, and won't be comparable with next year's, but after that [well, to be absolutely accurate, from summer 2019, because the last subjects won't be numerical until then, e.g. some languages] it will be OK?

Oh, no, forgotten the KS2 SATs changeover, so then we will have the first cohort who had the new KS2 SATs results, so:

• 2016 progress8 - last all non-numeric, old conversion.
• 2017 progress8 - only mixed, new conversion year.
• 2018 progress8 - current Y11, mostly numerical for the first time
• 2019 progress8 for a year or two: all numerical, progress measured from old Levels at KS2 SATs
• 2021? progress8 - numerical, measured from new-style KS2 SATs results

So non-comparability year on year until at least 2021/2022?

The problem you are thinking of, user is how the A-G grades were converted to numbers this year compared to last year. Lower grades counted for fewer points than previously, and it was worth 3 times as much to get a grade A student to an A than it was to get a grade F student to an E.
Next year when all GCSEs are numerical, this won't be an issue.

I may be renewing this incorrectly. But I think there are more points towards progress 8 for the highest grades if they are above expected progress. So i think the school gets higher for a student who scored an 8 who was expected to get a 7. Compared to a student who scored a 4 instead of a 3.

This would account for why progess 8 is higher for selective schools.

I'm sure it was the deputy head that said this to me. I have no link nor checked this out.

I think the 'banding' of Progress 8 (so average, above average, well above average etc - as shown by the colours on the tables) would be a sufficient level of accuracy for almost all purposes.

That would definitely explain it Clavinova, thanks for that. So it may well still be true that a good p8 is easier for a highly selective school, but the old 5+A*-C was even easier for them to score well at, and with p8 lower ability intake schools at least have a better chance of doing well. Outliers are a definite problem which can hopefully be resolved. Poor maths or English results will have a big effect too. Still not sure abolishing tables would be a good thing though - maybe just make them less public? I do think schools need to be accountable somehow.

I looked at the Colchester grammar schools and while the girls school progress 8 was exceptionally high, the boys was rather low which was curious

The EBacc result for the boys' grammar school is showing as 0% this year - last year it was 82%. From the school website it appears that the school are still entering their pupils for IGCSE sciences which won't have been included in the league table stats. Therefore the Progress 8 score for this particular school is quite meaningless.

Any minute now, our local paper will publish its annual "Every school in your area, listed from best to worst!" piece of clickbait. That's the title. It makes me so angry.
I hate that too. It feels like some schools that are deemed worst work really hard but have got an uphill struggle because of less parental support and more social issues which will affect progress/results, whereas the ones that are deemed best have had people jumping through hoops to get into them and lots of parental support and tutoring to help with progress/GCSE results.

Ouch! You can tell that the results have been really volatile. I teach in a top-100 P8 school and even though our A*-C went down by about 10% (largely due to Maths) P8 went up. The P8 scores for the top performing schools look much higher this year and the scores for the lower performing schools look much lower. The new system seems to have created greater inequality.
I can see the same happening in my subject (history) with the new specs this year. Some schools seem to have really struggled with delivering the new content in time for the exams. There was a poster on here the other day whose daughter's school were shockingly behind. I expect this summer's results in history will be very volatile with some schools doing much much better than usual and some seeing huge drops in results.

“Under Progress 8, the half a grade positive progress made by 27 students in a form class can get wiped out by three others who, for many reasons, fail to sit any GCSE exams.”

educationdatalab.org.uk/2017/01/outliers-in-progress-8/

It’s not ‘slips’ that have an impact, it’s kids who completely crash and burn, and these kids are not unusual. The DfE have said that from 2018, outliers having a disproportionate impact will be dealt with (but they are still investigating how). For this year’s set of data the problem remains.

My daughter cost her school 0.01 of their score last year by misreading a single instruction in the literature paper. That only has to happen 100 times for a school to crash from well above average, to well below
This isn't right. To move from well above average to well below average every child in the cohort needs to drop a full grade in every subject (or half the children drop two grades in every subject or equiv), so unless only ten or less children in the year, your dd's slip cost less than 0.01 of total school score. Factor in that most slips don't cost a grade and they have to to be in subjects that count towards prog8 and you will find you'd need an awful lot of slips to make much impact. (Plus all schools will have some children making such errors and they are often offset by lucky guesses by other DC or in other subjects etc).

I cannot think of any fair way to judge schools so maybe just abolish league tables

well, there is a way to make these measures statistically significant. If you take the average over 8 years, rather than concentrating on a single year at a time, these numbers do actually become meaningful.

Of course, 8 years is longer than any individual's secondary education, twice the length of the average teaching career and more than three times the length of any government system of measuring, so the numbers also become irrelevant for considering culture, teaching or system within the school, but nothing less than an 8 year average has any meaning anyway.

the Ks2 data is corrupt, the ks3 data is corrupt, the schools results are corrupt, and even if they were perfect, the comparisons between the are meaningless, you are looking at nothing other than spin on spin, so unless the difference between two schools is in DOUBLE FIGURES, over a period of YEARS, ( and sometimes it is) forget it

I am a little more pro Progress 8 because where I work looks like the bees knees and that is an accurate representation of the school's results. We had a very weak cohort last year who did exceptionally well but this was as much down to the 'nature' of the year group. They were incredibly hard working and focused and behaviour was excellent. The current Y11 are different...

Equally I think P8 will help SN pupils and able pupils because their progress is as important as the old C/D borderline pupils who used to take so much focus away from them. I cannot think of any fair way to judge schools so maybe just abolish league tables.

meaningless drivel, the whole lot of it. none of it has any statistical integrity. My daughter cost her school 0.01 of their score last year by misreading a single instruction in the literature paper. That only has to happen 100 times for a school to crash from well above average, to well below. in other words, in the average school, half of all pupils to slip up a little bit once in one paper, or a quarter of all pupils to slip up twice, or even 10 (5%) rushed careless pupils to make a little mistake in each of their papers. How is it in any way a reflection on the teaching if my daughter reads "answer 1 question from section 2" as " answer 2 questions from section 1" or similar, can't remember exactly what it was, but something like that.

Proof that Progress 8 is bollocks

Thornden (because it gets mentioned so often)
has Progress 8 of 0.24
but the "confidence interval" is 0.1 to 0.49

So the school is "above average" but they have no idea if its nearly "well above average" or actually just "average"

Yes, the 2 decimal places gets me every time too. Why do they pretend they are that accurate?

Our 5+ in English and Maths is pretty much the same as our C+ in English and Maths has been historically. The new GCSEs have hit different schools and different departments in completely different ways depending on school policies, etc.

My school are quite happy with the rankings and league tables, because we're near the top for our county and have been for quite a few years. Dd1's school is NOT happy with them because they aren't doing so well this year, not sure why really as the actual results seem very good, but the progress 8 has but them hard.

PS bang on about the two decimal places. Talk about spurious accuracy.

I don't understand why they are reporting the % reaching 5 - as others have said I though that 4 was the equivalent to a GCSE grade C. I just looked at my son's school, which last year got 55% on the % grade C in English and Maths (this reflects its intake) - this year the headline stat that gets reported is half that (whereas the % reaching 4 is about the same). How totally demoralising for the schools - I'm sure there are lots of parents who will take one look at the % pass that gets promoted most heavily and think bloody hell, not sending my child there (especially if they then compare it to the % grade C from last year). Mind you, I guess all schools will have to deal with this.
Frustrating...