Cheque book selection.
Having been to a school that was a dumping ground for the factory trash (as the deputy head said) I left school with next to no qualications in anything except engineering and tech drawing.
Nothing stopped me going along the modular route to the ATPL and eventualy to a Jet command, I suspect determination rather than accademic qualifications are required.
However having seen the antics of a number of training providors when helping new (F)ATPL,s get jobs I can only conclude that the size of daddys cheque book has more to do with job placement that flying ability.
These entry exams are a smoke screen for the airline personel departments who are as stupid as ever when it comes to pilot recrutment and can be fobbed off with the feeling that they are getting a "select" band of new pilots when the truth is the only real course entry requirment is to have the finance in place.
On a personal note I far prever flying with people who have done the modular course, they are by and large much better real world pilots.