The Universities Admission Index (UAI) was used in New South Wales and the Australian Capital Territory, Australia, as the primary criterion for entry into most undergraduate-entry university programs. It was a number between 0 and 100 (though those below 30 were not reported), occurring in increments of 0.05 and indicating the rounded percentile rank of a student who undertook the Higher School Certificate or ACT Year 12 Certificate with a valid quantity and combination of units of study. It was replaced in N.S.W with the Australian Tertiary Admission Rank (ATAR) in 2009. Prior to the UAI the ACT used its own Tertiary Entrance Rank Overview The UAI was awarded to students on the completion of the HSC in NSW and the completion of an ACT Year 12 Certificate with a "Tertiary Package" in the ACT - both at the end of year 12. It provided a percentile ranking of peer students of the same age. In NSW, the UAI was determined by a combination of the public HSC exams common across all schools at the end of Year 12 and continuing assessment. Assignments and exams in Year 11 served to prepare students for Year 12 but were not in any way involved in the calculation process. In the ACT, the UAI was determined by ongoing assignments and exams spanning through both Years 11 & 12. The ACT Scaling Test (AST), sat by tertiary students, linked a student's ability with the school's mean score in each course and was used to scale students in different courses and schools. UAI scores were not directly equivalent to a percentile rank among those who completed Year 12 (i.e. a UAI of 99 was not equivalent to placing in the top 1% of the state). The statistical distribution of UAI scores in 2004 found that 1.6% of students who completed Year 12 scored at or over a UAI of 99. UAIs are awarded in increments of 0.05. The UAI's predecessor, the Tertiary Entrance Rank, was different because it defined the student population as only students in year 12. The UAI attempted to rank students who did not progress to their senior years of High School, by estimating what they would have got. This keeps the rank consistent throughout the years despite fluctuating Year 10 drop-out rates as the rank was always measured relative to a Year 10 cohort, with the ranks of the drop-outs being