Before revision:  a test given annually to all Australian primary school students in grades 3, 5, 7, and 9. Students who perform in the `below standard' band constitute approximately 3\% of the sample, with the remainder performing at or above standard, requiring that a proposed classifier be robust to imbalanced classes. Observations for students in grades 5, 7, and 9 contain data on previous achievement in NAPLAN.
After revision:  a test given annually to all Australian primary school students in grades 3, 5, 7, and 9.