that is only the minimum threshold
Of course it is the minimum threshold (as it seems surprisingly low for such a high-achieving school - a student could achieve only three 7s and five 6s and meet the criteria for entry!) and when oversubscribed, the children with highest overall grades will be most attractive candidates for places. I don't have a problem with a selective school selecting the kids with highest potential grades, especially knowing that in reality if you call up immediately after the results are out and they are good enough, they will not have 'over-offered' based on predicted grades and therefore have several places available for those who are able enough academically / keen enough to bother to call.
In fact, this particular 6th Form offers less 'value added' than a lot of other 6th Forms which are just as easy to get to, so if our DC don't get an offer there, at least there are excellent local alternatives (particularly if one has been fortunate in the ballot for a nearby college).
That said, I do share some concerns over predicted grades - a bit like the university process also - where is the moderation across schools/the country? We all hear horror stories of kids being told they will get certain grades that have been vastly overinflated by teachers, and also others whose teachers are far too harsh.
Surely it's more sensible to wait and see what the actual results are and offer places based on that (taking into account other factors if too many eligible candidates with identical grades have applied?)
But if offers for schools need to be made so that families can plan for the start of 6th Form and all the enrolment paperwork can be completed with sufficient time, using predicted grades is as good a criteria as any. If the chosen students in reality don't get as good grades as someone on the waiting list, then they still have achieved the minimum of a 7 for their A Level subjects so have a negligibly different chance of succeeding there compared to the 'higher' GCSE-achiever. It is also pretty unlikely that any students predicted 8s and 9s will actually end up with significantly lower than that required as the 'bare minimum' for the school. In general schools are pretty reluctant to predict 9s (well they are at my DCs school, even though well over 70% of GCSE grades actually achieved each year are A*,8s and 9s and 99% of GCSE students achieve 9-6 grades in all their subjects) so it is probable that the majority of predictions should be fairly accurate.
If predicted grades aren't the criteria for a selective 6th Form, then what should be? This isn't meant to be a confrontational question - I have been thinking about a potential answer and have come up with nothing apart from abolishing selective 6th Forms altogether....