Joker, don't forget the impact the IB course has on student numbers at Newington. Almost a quarter of year 12, are dong the IB and this naturally bits into the HSC. Additionally, those students are the most talented and academic ones in year 12. If the IB Didn't exist at Newington, our HSC results would have been very different.
Also, any HSC review needs to assessed against the total number of students a school has in its year group undertaking the HSC. For example I believe Joeys would have about 170 boys doing the HSC. But Knox Grammar might have somewhere between 300-350 boys for the HSC. twice the number so their results can be expected to be greater. The rankings are based on the raw scores and make no reference to year group sizes. I notices PLC Pymble did well. Like Knox they have about 300 students in year 12. In one subject they accounted for 9% of the candidates doing the HSC. Of course they are going to dominate the results. Equally, James Ruse have 7, 4 Unit Maths and Science classes. Hence, these numbers will ensure a vastly better outcome in the HSC rankings.