Spelling and numeracy at high school level continue to be the ACT's greatest educational weak points when the territory's relative social advantage is taken into account.
The latest raw scores of literacy and numeracy results published in Monday's Canberra Times show most Canberra schools perform well above the national average in reading, writing, spelling, grammar and numeracy.
But when each school's student population is analysed for levels of socio-educational advantage, only a very select group outperform schools with similar student bodies. The rest lag behind Australia.
The index of community socio-educational advantage (or ICSEA) is an important feature of the My School website, which has published 2013 results from the national assessment program for literacy and numeracy. The index compares the performance of each school with 60 schools across the country that have the same socio-educational mix of students.
On raw scores, the ACT is the top or equal top performing state or territory in Australia on every single measure of NAPLAN at every year level tested. But the ACT also benefits from higher ICSEA scores, which reflect the city's demographic and middle-class advantages.
Worryingly, ACT schools perform nowhere near as well as other schools with similar ICSEA ratings, as the league tables demonstrate.
Only a handful of schools - notably Jervis Bay and Wanniassa - perform well in advance of other schools with similar student mixes.
While the raw scores of both schools place them near or at the bottom end of results, they come out at the top of the pack on most measures of literacy and numeracy when compared with other schools across Australia with similar student bodies - in this instance, a high proportion of indigenous and non-English-speaking backgrounds.
The ACT ICSEA ratings are generally better across the primary years, where more schools are performing better than similar schools and the differences in scores are greater.
But by the high school years, that number dwindles down to just a handful of schools across the literacy and numeracy domains and the point difference between their results also narrows considerably.
By year 7 spelling, just Wanniassa and Amaroo achieve better outcomes than similar schools and in numeracy, only Wanniassa does.
In year 9 spelling, Wanniassa, Orana Steiner and Merici College performed better than similar schools, while in numeracy, just Covenant College and Lyneham High came above the line.
The Australian Curriculum, Assessment and Reporting Authority, which administers NAPLAN testing and the My School website, opposes the publication of league tables such as those published by The Canberra Times.
But chief executive Rob Randall said ACARA did support ''fair comparisons that drive school improvement to be made''.
This year, the ICSEA calculations were refined to use more accurate measures of parental education levels and employment status.
''ACARA developed the Index of Community Socio-Educational Advantage to enable fair and meaningful comparisons to be made among schools with students from similar levels of socio-educational advantage,'' Mr Randall said.
''Differences in student achievement between these statistically similar schools are due to what the schools do and not the families from which the students come.
''Having this data allows schools and principals to learn from each other and start the conversation about what is working and where improvements can be made''.
The ACT Education Directorate's director of planning and performance, Tracy Stewart, said some factors needed to be taken into account when assessing the ACT's performance.
''Firstly, we have not seen a decline in performance against similar schools on last year's results,'' Ms Stewart said.
She also noted that a margin of error meant statistically small point movements could not be interpreted as significant.
Ms Stewart said the directorate was always looking to improve performance and she noted international testing undertaken last year through the Program for International Student Assessment showed the ACT was closing the gap in year 9.
She also noted the changes to ICSEA calculations this year had moved some Canberra schools into a higher bracket of advantage - which would affect their rank when compared with similar schools.