What is the optimal size of a high school?

Adept Economics Director Gene Tunny was quoted in the Sunday Mail on 16 July 2023 regarding the surge in Queensland state high school enrolments. Analysis conducted for the newspaper suggests that some schools could end up with 4,000+ students in coming years. Among other things, the Adept Director suggested to the newspaper that such large school sizes could be counterproductive and in excess of the optimal school size (see excerpt below).

It appears that there is such a thing as an optimal school size, where benefits from expanding the size of the school, such as economies of scale (e.g. sharing overhead costs), end up being balanced by costs of expanding the size of the school, such as adverse impacts on learning outcomes or worsening student behaviour. Surprisingly there has been a limited amount of research on this issue. That said, the research available tends to support the views of the Adept Director.

A high-quality 2004 systematic review by the EPPI Centre at University College, London, found that for secondary schools:

“For some outcomes larger schools appear to be better, for other outcomes smaller schools seem better.

The larger the secondary school, the better pupils’ results and attendance, but only up to a certain school size. The estimates of the ideal size range from about 600 to 2000 students.

Pupils felt less engaged with larger schools.

Teachers felt less happy with the climate in larger schools.

Some kinds of violent behaviour rose as school size increased while other kinds of violent behaviour increased as school size decreased.

Costs per pupil decreased as school size increased.

Because of the research methods used, all these results should be considered tentative.”

That is, there are pros and cons with larger school sizes and at some level the cons outweighs the pros and there is an optimal size. The precise optimal size, however, is unclear and could be anything from 600 to 2,000 students.

None of this suggests that any particular school has too many students. Much depends on the quality of the school leadership and the socio-economic background of students which can have a significant impact on school performance.

Furthermore, Queensland high schools typically have six grades of students, while American and British high schools have four grades. This may mean the optimal size of a high school is higher in Queensland and other Australian states than in the US or UK, if it is the number of students in each grade that is the relevant driver of outcomes.

Nonetheless, projected school sizes of over 4,000 students appear to raise concerns and require a policy response.

Excerpt from the Sunday Mail report “Qld state high school enrolments surge”, 16 July 23

Brisbane-based economist Gene Tunny said schools with enrolments in excess of 3000 students tended to have increased behavioural, social and learning problems.

Mr Tunny, the lead author at consultancy Adept Economics, said one of the challenges planning for future growth was that some schools were simply more popular among parents than others.

“The state government is very conscious of this but one of the things identified is that some schools are overcapacity and some are under-utilised,” Mr Tunny said.

Mr Tunny suggested that schools could be more rigorous or firm with accepting out of catchment enrolments to spread the load more evenly.

“One of the challenges is, for whatever reason, parents want to send kids to more highly regarded schools,” Mr Tunny said.

“Being rigorous or firm on where parents can enrol will help. But there is also the potential to increase the capacity of existing schools too.

“Schools with large oval, it could be OK to lose some of it to increase capacity for a building to relieve pressure.”

Published on 20 July 2023. This article was prepared by Adept Economics Economic Director Gene Tunny with input from Research Economist Arturo Espinoza. For further information please get in touch with us via contact@adepteconomics.com.au or by calling us on 1300 169 870.

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