@FancyBiscuitsLevel -
firstly not everyone tutors for the 11+.
The vast majority do tutor for 11+ (either by paid tutor or parents do it themself).
foes removing the top 25% effect the next 25% students? If kids are taught in sets, that’s removing the top set of maths, those who wouldn’t be in that set anyway, would it negatively effect them to have those kids taught elsewhere?
It does, this is because research found that im the selective area there is negative effect on nearby schools by many reasons, for example
https://www.durham.ac.uk/news-events/latest-news/2023/08/grammar-school-system-does-not-boost-grades-and-could-be-detrimental-to-some--/
"The researchers suggested this could be due to the negative effects of stress and competitiveness generated by the selective system, which could impact on pupil wellbeing.
For those pupils in selective areas who do not get a place at grammar school, they may also experience a lack of role models, a sense of failure and higher concentration of disadvantages pupils in school, which may impede progress"
you said up thread that the GCSEs of grammars are down to tutoring, I was just explaining in our area there aren’t many who tutor at gcse level in the grammar system. The money in tutoring at that level isn’t getting 8s and 9s, it’s turning 5s to 6s.
Ok maybe in your grammar area it is, in the grammar area I know, a lot of money in tutoring in grammar school for pushing their kids to top. GCSE grades, if not doing more than the local comp. Because the grammar school parents believe in tutoring, and they are normally those who can afford tutor (they did that from primary school age anyway)