The ACT Government commissioned Monash University Professor of Statistics Rob Hyndman to review the system in response to claims the process used to convert students' Year 12 marks into nationally recognised Universities Admission Index scores was flawed.

Yet while he found there was "no evidence" territory students were being disadvantaged by the use of NSW student data to convert ACT scores into UAIs, Professor Hyndman conceded the use of ACT Year 9 literacy and numeracy results could be explored for an improved like-for-like comparison.

However, the ACT Government has ruled out any changes.

Greens MLA Deb Foskey said earlier this year the statistical process used to compare ACT marks with those of NSW students was not working and many students missed out on the university courses they wanted.

At the heart of her concerns was the use of NSW academic results to convert raw ACT Year 12 scores into UAIs.

To convert ACT scores, administrators use a table based on the academic performance of all NSW students in earlier Year 10 School Certificate exams.

This allows the results of Year 12 students completing tertiary-entrance packages to be compared with those of the rest of their year.

Dr Hyndman, who devised the ACT conversion system, has argued the use of the data is necessary due to the territory's highly mobile student population and the lack of such exams in the ACT.

But Dr Foskey said it was unfair to apply results from NSW, where the socio-economic background of students varied more widely, to the ACT, where incomes and education levels tended to be higher.

The conversion process meant ACT students, who because of their backgrounds were expected to perform strongly, were receiving lower UAIs than those from comparable socio-economic areas, such as Sydney's North Shore.