Depends if you are talking about the super-selectives or the selectives.
With the super-selectives they may just take the top 60 or whatever scorers. If you've got 600 kids sitting the exam then a question missed out, a few minutes wasted working out what the question means - these can mean the difference between getting a place or not.
Parents therefore tutor a child so that they know exactly what type of questions come up, how to tackle them and how to pace themselves to finish the paper.
With the selectives it's generally a case of achieving x points in which case the extra-tuition does the same thing as above but isn't needed to the same degree.
The competition for grammar schools is far greater today:
- there are fewer of them
- in grammar school areas such as Kent, the cohorts in the non-grammar schools will have a very different ability mix than those in non-grammar areas so parents are extra-keen to secure a place.
- the current economic climate and the incredible cost of school fees today means that parents who would formerly have chosen Indies and now realising that a few £thousand invested now in a prep or tutoring and a place at a grammar will save them a small fortune.
- parents have often made a significant investment in terms of an inflated house price in a grammar school area and are determined to get the return on that.
- everyone else is doing it so you need to make sure your child is prepared just as well.
It's a whole different ball-game and demographic to the situation in the '70's and '80's.
Just a shame that all state secondaries can't perform well. Our local one (which is CofE so selective by the back-door) only gets 39% of their students to university of which only 4% to RG. I went to a grammar where 99% went to university and over 50% of those were Oxbridge or RG. I remember the shock on everyone's faces when one boy came in to say that he was leaving to go into the city after A'levels rather than applying to university. Many aspirational parents would look at our local school and decide that a school where less than half the students aim for university will not have the ethos, drive or aspirations for their pupils success that they want. So you max out any means you have of getting that grammar place.
I don't think it means that students who are not grammar school material are getting in because they have been prepared - you still have to be bright enough to make the most of the preparation. But it does mean that some very bright students won't get in because they haven't had the same preparation.