nah, there's not that much pressure to perform at our school - they want the top 30 or so to perform, but they realise that everyone has their own talents, so as long as you've got a certain level of aptitude (ie proficiency with respect to literacy, writing skills, communication etc) they don't mind too much. What Dr Vallance could have been referring to was that there are only a limited number of places available to applicants in yr 9/10 etc and that you'd need to do well in the entrance exams to get in.
Edit: OK, this is a fairly redundant comment now.