Nearly 30 academic studies of public and private school outcomes in Australia have been published in the last 15 years. The first comprehensive review of these studies shows that the vast weight of evidence is that public schools achieve similar outcomes to private schools. The report has just been published by Save Our Schools.
While raw comparisons of student outcomes in public and private schools generally show higher achievement in private schools, such comparisons are misleading because public schools enrol the large proportion of disadvantaged students. On average, these students have much lower results than students from higher socio-economic status (SES) families. Fair comparisons of school performance use various statistical techniques to adjust for differences in family and school SES and other background factors.
Studies that have adjusted for a range of student and school characteristics show no significant differences between the results of students from public, Catholic and Independent schools in national and international tests and in university completion rates. Public school students appear to achieve higher university grades than private school students despite the latter achieving higher university entrance scores. There is mixed evidence for Year 12 completion and workforce earnings.
Seven studies of public and private school results on national and international tests in Australia have been published in the last five years. Six of them show no statistically significant differences between the results of public, Catholic and Independent schools. The one exception to this used a flawed measure of school SES to adjust the raw test scores that has since been jettisoned by the Australian Curriculum, Assessment and Reporting Authority (ACARA) as unreliable. Moreover, it failed to take account of differences in family SES.
Three studies of Year 12 completion in recent years show mixed results. One found that students in Catholic and Independent schools are more likely to complete Year 12 than students in public schools. Another found an advantage for Independent schools over public schools but no difference between public and Catholic schools. The third study estimated that the Catholic school effect ranged from slightly negative to slightly positive compared to public schools, depending on different assumptions. These studies adjusted for family SES but did not include a measure of school SES.
Six other studies have estimated the impact of attendance at public and private schools on university entrance scores in the last 15 years. Four found a small advantage for Catholic and Independent schools. Two other studies found a small advantage for Independent schools over public schools, but not for Catholic schools. The differences in adjusted scores are very small and may be over-stated because a measure of school SES was not included in any of the analyses.
Six studies have analysed the impact of school sector attendance on first year university grades in the last ten years and all found that students from public schools achieved higher grades than students from Catholic and Independent schools.
Three studies have suggested that the contrast between the advantage of private school attendance on university entrance scores at the end of Year 12 and their disadvantage in first year university is due to private schools artificially boosting university entrance scores by intensive coaching to improve access to university. These students do not appear to do as well at university because they have to work more independently.
Three studies have compared university completion rates for students from different sectors. One estimated that the Catholic school effect ranged from slightly negative to slightly positive compared to public schools depending on assumptions made, while the other two found no significant differences in completion rates between students from public, Catholic and Independent schools.
Few studies have attempted to determine the effect of school sector attendance on labour market outcomes. The evidence from two studies on later earnings in the work force is mixed. One found a small earnings gap favouring Catholic school students over public school students and the other found no significant difference in weekly earnings between public, Catholic and Independent school students.
In summary, the evidence from academic studies overwhelmingly indicates that there is no advantage in attendance at private schools for a range of education outcomes. Students from the same social background do as well in public schools as in Catholic and Independent schools.
The findings of these studies suggest that parents are effectively paying for something else other than education results by choosing a private school. They may be paying for a religious education, ornate facilities, extra-curricular options, social status or a future employment network. This of course is their prerogative, but they should be under no illusion that this choice will deliver better education outcomes for their children.
Trevor CobboldA Review of Academic Studies of Public and Private School Outcomes in Australia