GATs are pointless.
I knew a guy, year above me in High School, absolute genius; unfortunately he also had asperger's and was treated rather poorly by his parents so was sent to boarding school even though they lived in the same city. Anyway, he took science classes 3 or perhaps 4 years past his year bracket, so as soon as he hit VCE level (and subsequently University) he had to take the GAT every year until he finished High School. After 2 he literally handed in his paper blank every time as he'd done it so often.
The best thing to happen to Australian education is the nationalisation (although I'm not sure if it's fully implemented yet) of the education system. Because of the way students are ranked by percentile, not average grade, and the different structures of courses, it was ridiculously harder in Victoria/NSW/ACT (and possibly SA/TAS) than the other states.
Have I accidently stumbled on to BigEducation?