Private, Catholic schools do add value to students' results

Analysis of students’ Tertiary Entrance Aggregate, from which ATAR is derived, revealed substantial effects of school sector. Students from Catholic and independent schools performed at 0.24 and 0.38 standard deviations higher than their peers in the government sector, again once accounting for the effects of socioeconomic status, prior achievement, gender and language background.

The study included analysis of students who changed school sectors between Years 9 and 12. It concluded that the Catholic and independent school sectors were associated with increases in academic performance of six and eight percentiles, respectively, compared with the government sector.

Therefore the higher tertiary entrance performance of students attending Catholic and independent schools cannot be attributed to the differences in the social and academic profiles of each sector’s students.

Socioeconomic background not as important as thought

This study also demonstrates that students’ socioeconomic background is not nearly as important as often claimed. Student socioeconomic status is a weak predictor of students' ATARs. The very much stronger effects of prior achievement (Year 9 NAPLAN performance) on tertiary entrance performance cannot (at all) be attributed to socioeconomic status.

The absence of strong effects of socioeconomic background on tertiary entrance performance makes theoretical sense. The knowledge and skills assessed during and before Year 12 are overwhelmingly taught in schools; even the most highly educated, wealthiest, or most cultured parent would have great difficulty with the depth and breadth of a typical Year 12 student’s subjects.

These findings show that Catholic and independent schools “add value” to students' tertiary entrance performance in Victoria in terms of higher scores. Here “value adding” is defined as increasing student performance beyond that expected by students' prior achievement.

This conclusion of substantial sector differences in ATAR does not necessarily contradict studies that show small or no sector differences in NAPLAN. It may be the case that school sector differences in student performance are trivial in primary school but increase over the school career and are sizeable in senior secondary school. At least this seems to be the case for Victoria.

Alternatively, Year 12 assessments are “high stakes” tests, whereas NAPLAN and PISA are “low stakes” tests in that there are no consequences for students for excellent or poor performance. Schools are more likely to devote much greater resources to “high stakes” tests.

Since the early 2000s Victoria has been a leader in allowing analysis of administrative data on student performance in Year 12. It is hoped that analysis of similar data of senior secondary students from other states and territories will help us understand the extent and nature of school sector differences in Australia.