Low average VCE score by P40 or MSS measure does not necessarily mean that the teachers of a school do a bad job or provide a poor environment for the gifted students. Some schools (e.g. Mac.Robertson Girls' High School, Melbourne High School) are highly selective and take only the fast learners, some private schools attract fast learners by offering them scholarships, etc. On the other hand, many schools accept all the applicants (or even specifically encourage applications from students with learning disabilities) but still provide an excellent environment (accelerated programs and advanced classes) for the gifted students.
Some subjects are easier to get high VCE Study Scores than the others due to the strength of competition within that study, thus, by "optimising" the choice of the VCE subjects a school can artificially increase its median Study Score. Girls on average seem to produce better VCE results than boys. Finally, academic progress is only a part of the services that secondary school provide to their students. Still many parents consider high VCE study scores to be very important in their choice of the schools.
Some private schools encourage gifted students to take International Baccalaureate examinations instead of VCE, thus, lowering their average VCE score.