4% of Oxbridge entrants are private schoolers compared to around 70% of state schoolers (the remaining 26% are, presumably, overseas students). This suggests that a student is more likely to get into Oxford or Cambridge if they attend state school.
Careful using percentages like that; it's meaningless without knowing how many applicants there are. I would be surprised if the rate of success for private schoolers isn't higher than for state schoolers.
I experienced both private and state schooling during my education years (admittedly this was over 20 years ago, so things may have changed) - my thoughts;
- Private schools tend to have entrance exams (although they are not all equal!) - this means that all students have some level of academic ability which is suited to a wholly academic environment (vs state schools that might lay the foundations of a vocational career / apprenticeships)
- Noted on the point above about QA, the other component is parents are much more likely to take action on any report from the school of their child being disruptive given the money they're paying "I didn't pay all this money for you to mess around"
- There were issues in both types of schools in my experience, but with parents who were teachers in each, I had some first hand accounts from two secondary schools both in the same area, one private and one state; the latter had significantly more problems with behavioural issues, drugs and weapons, and this was 20 years ago when pupils hadn't yet fully grasped the "I'm entitled: you can't do anything to me" tagline
- Private schools will often add significant extra-curricular value, e.g. clubs, societies etc.. as these schools see this as key additional offerings. You
can get these in state schools, but generally only where you have a particularly enthusiastic and dedicated teacher, but even then they're unlikely to get any funding to actually support it (unlike in a private school)
- Preparing for life: well, to think a private school is totally sheltered and full of very wealthy and innocent pupils is inaccurate - they're still kids and still get exposed to much of the same, there's still bullying and all the usual social issues associated with schools, it's just that within the school boundaries it tends to be much more heavily policed in a private school
My conclusion; I remain to be convinced there's much benefit to sending a child to a private school for primary-level education, unless the schools in the area are particularly bad. When it comes to secondary level, I think it depends on the child and your own circumstances. If your child wishes to pursue a career as a mechanic, I think there's less to be gained from a private school, but if your child has a keen interest in academic subjects then a private setting may prove to be more value-adding, particularly if they're bright and/or studious. How you measure that value against how much £££ it costs to send them through that, that's tricky and something only the parent can decide.