The OP system made use of preferences which rated schools on a scale. It scales on two levels, one within the school and the other, across the school system. This model made use of a metric referred to as “Subject Achievement Indicators (SAIs)” to determine where students fall based on their subject areas.
The OP demonstrated a biased system which favoured schools with better resources. It placed focus on topics that pass as highly academic, which are often the exclusive preserve of specific schools. These were courses one could find in private schools, thereby placing students of private schools above other others.
OP was also criticised for using 25 bands as its overall achievement indicator. This indicator was criticised on the grounds that it is not an adequate representation of students’ abilities. However, with the ATAR, there is a precise method, which makes for the representation of all students. ATAR makes regard for all schools, whether private or located in poor locations.