A rabbit hole indeed - maybe a glass of wine instead next time!
Theres a VERY big reason why no one, ever, uses the government datasets.
The difficulty you have here is that a few different datasets are being mixed together, which makes the comparison look clearer than it actually is.
The figure you’re quoting from the government site is AAB or higher in facilitating subjects.
That’s a very specific accountability metric, it only counts certain subjects and depends on particular combinations , so it doesn’t measure overall A-level performance.
That’s why all schools (inc TM & FH) always publish the headline results like A-A or A-B** instead of gov. numbers.
On those like-for-like figures, the most recent results show around 82% A*-B at Tormead vs about 76% at FH, so Tormead is still ahead overall. Im not affiliated with TM, but i work a lot with local schools, both state and indepedent and use this data, and its important to know what it means and how to use it.
The subject tables on the government site are also "entries" rather than "unique pupils", and the cohorts are quite small, unlike a large maintained secondary, which is where the data starts to become slightly useful. The site shows 55 students in the Tormead A-level cohort and 37 at FH.
With numbers like that, a difference of two or three pupils can swing the DfE percentages quite a lot, so comparing subject uptake between schools isn’t especially robust.
The Good Schools Guide figure you mentioned also appears to be the same AAB facilitating-subjects metric pulled from the government dataset, rather than the schools’ headline results, so again it isn’t directly comparable with overall A-level outcomes. This is likely because they have data gaps from schools websites and an easy way to fill all of them is to scrub the DfE website to plug holes in their pay-to-view articles.
It’s also worth looking at wider academic pictures, something the state maintained sector do a lot, as it gives the very best indication of attainment:
GCSE results reflect the full cohort, whereas sixth forms are naturally filtered because some pupils leave after GCSE. Tormead’s GCSE results are significantly stronger, yet it still sends a number of girls elsewhere for sixth form, nearly half leave for co-ed selective sixth forms and some state. Even with that, its A-level cohort is still larger than FH’s. FH GCSE year groups are obviously bigger than 37, so quite a number of pupils must be leaving before sixth form, which inevitably changes the academic profile of the group that stays.
Finally, if you look at university destinations, there’s a fairly clear difference as well, with Tormead consistently sending more girls on to Russell Group and Oxbridge universities.
I admire the level of detail you’ve gone into on the government website (a deep dive on a Saturday evening!) but I’m not sure those particular tables really support the conclusions you’re drawing from them.
Again, like you say, both are stellar good choices, but, as an education data nazi at work, i find using data to achieve your point of view is misleading, and wine is definitely the better choice.
In summary:
Tormead gets better 'headline' results year in, year out at A-Level, better uni destinations, and, as a year 7 co-hort, their results as a group, at GCSE, when tested, are many miles ahead, showing the academic profile of the student pre-sixth form.
I imagine if everyone fro Tormead actually stayed from GCSE to A-level,.as did those at Farnborough Hill, statistically the gap would be huge between the two establishments.