Private Schools Are No Better Than Public Schools

Another academic study has found that the quality of private schools in Australia is no better than public schools. It also found that there is a strong and positive association between the socio-economic status (SES) of a student and their test scores. It is the fourth study in the last year or so to show that there are no significant differences between the test results of private and public schools in Australia after taking account of the socio-economic background of students and schools.

The core result of the paper is that, after controlling for a number of school and student characteristics, “school quality does not depend directly on the sector of the school” [p.15]. It says that the main determinant of the higher raw test scores observed in private schools is the higher socio-economic status (SES) of students attending private schools.

The data strongly supports the simple proposition that the main determinant of higher scores in non-Government schools is the higher socio economic status of the students that choose to go to non-Government schools.
….what seems to be driving the (raw data) observation that non-Government schools achieve higher scores than Government ones, is not the result of an inherent higher quality of non-Government schools. It is rather the result of the more privileged high socio economic status students self-selecting into non-Government schools and taking their existing advantage with them to these schools. [p.16]

The study found a strong positive association between SES and test scores at both the individual student level and the school level. An individual student from a higher SES is much more likely to achieve higher scores, irrespective of the school they attend. The study estimated that the reading test score increased by 9.5 points for every one point above the mean of the measure of SES. The increase was 11 points in maths and science.

The study was conducted by academics at the National Institute for Labour Studies at Flinders University and published by the Institute for the Study of Labor in Bonn, Germany. Its findings are based on a statistical analysis of the results from the 2009 Programme for International Student Assessment (PISA) for reading, maths and science in each school sector. It controlled for a number of student and school characteristics apart from SES, including Indigenous background, location, school type, time spent on subjects, student/teacher ratio, shortage of qualified teachers, computers per student and absenteeism.

The study also showed that a small part, roughly six to seven per cent, of the total variation in test scores is explained by unobserved factors after controlling for student and observed school effects. This residual effect is interpreted as a measure of school quality including influences such as the learning environment of the school, ability of teachers, leadership, etc. This finding suggests that the part of school quality that is hard to quantify and measure in the data, “has much less of an independent effect on student outcomes than we may sometimes be asked to believe” [p.9]

The study also tested whether this residual measure of “school quality” was significantly smaller or larger for government schools compared with private schools. It found no significant difference for reading, maths or science.

This is a simple but powerful result, which suggests that when we compare the quality distributions between Government and non-Government schools, we cannot find any statistically significant difference. [p.14]

Similar tests were conducted comparing the estimated quality of government, Catholic and Independent schools separately. In the case of reading and science, the estimated school quality does not differ significantly between school sectors. In the case of maths, government schools performed better than Independent schools while Catholic schools performed slightly better than government and Independent schools. However, the study warns that these results should be treated with caution because of the small sample sizes when private schools were split into Catholic and Independent schools.

The findings of the study are consistent with those of several studies in the past year or so showing that private schools do no better than public schools. The results from the OECD’s Programme for International Student Assessment (PISA) in 2012 show no statistically significant difference in the results of public, Catholic and Independent school results after taking account of the socio-economic background of students and schools. The report said that:

…students in the Catholic or independent school sectors bring with them an advantage from their socioeconomic background that is not as strongly characteristic of students in the government school sector. [p.35]

A study published in the Economics of Education Review last December by economists from La Trobe and Monash universities shows that the Catholic school performance has declined since 1980 relative to government schools. It says that the advantage that Catholic schools once held over government schools has virtually disappeared and attendance at Catholic schools may now lead to lower completion rates in secondary school and university. It noted that the decline in the Catholic school performance over the period 1980–2000 coincided with a large increase in funding. This raises questions, it says, about how well these increased resources have been used.

Another study published in the same journal by an economist at the Melbourne Institute for Applied Economic and Social Research shows that the decline in Australia’s performance in international tests over the last decade is primarily due to falling results in private schools, the falls being similar in both Independent and Catholic schools.

At the school level, the declines in performance of schools have not been associated with many of their observed characteristics, other than that the declines appear to have been concentrated among private schools. Where private schools once generated better outcomes than public schools, given the compositions of their student bodies, this was not the case after 2003. [p.237]

The study noted that the decline in performance in Independent and Catholic schools occurred despite substantial increases in government funding over the period. These funding increases greatly exceeded those for government schools whose results appear not to have fallen. This suggests that private schools have used their funding increases much more ineffectively than government schools, raising the question of what benefit the nation’s taxpayers have received from this expenditure.

The new study from the National Institute for Labour Studies concludes that there is no evidence that private schools are any more efficient in utilising resources than public schools:

This paper does not find any evidence that non-Government schools show any capacity to utilise the funds at their disposal more efficiently than their Government school counterparts….
…. Our paper provides evidence that even after we subject some of the best data available to probably the most sophisticated methodological testing available, we can still find no evidence that the non-Government sector puts funding to a more efficient use than the Government sector. [p.16]

It says that its findings provide support for a new funding model based on improving equity in education.

Our paper suggests that the Australian policy for a sector-blind distribution of school funding is supported by the evidence and that the main arguments for the use of public funding to support school education should be on equity grounds alone, as the efficiency of the two sectors is shown to be indistinguishable. [p.16]

This is exactly what the Gonski funding model is designed to do. It should be fully implemented nationally and not continue to be dismembered by the Federal Government.

Trevor Cobbold

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