In some countries, educational policies are tweaked to affect class size, teacher numbers and school resources in order to significantly improve school results. In the UK, it is a different story according to new research - class divide is what has the most impact on student performance

The research, conducted by Politecnico di Milano and Lancaster University Management School, uses in-depth analysis of Programme for International Student Assessment (PISA) data from 2015, capturing results of standardised tests for 15 year olds. Looking specifically at performance in mathematics across nine countries – Australia, Canada, France, Germany, Italy, Japan, Spain, UK and USA – the study aims to get a true picture of the factors that help students achieve, in a bid to help improve educational systems across the world.

Findings show social class has the most bearing on performance in five out of the nine countries studied – including the UK. In the majority of countries, the other most important factors affecting student performance are self-reported anxiety towards tests and students’ own motivation.

A well-disciplined classroom is more important to students in the UK and USA, than in other countries. The proportion of disadvantaged students in a school is one of the four most important factors in terms of school performance in all countries, bar Japan.

Geraint Johnes is Professor of Economics at Lancaster University Management School and co-author of the paper, Student and School Performance Across Countries: a Machine Learning Approach, published in the European Journal of Operational Research. He said: “Our research suggests the UK’s most effective schools are defined by their size and the social class of their students, rather than management teams and availability of teaching resources - which are traditionally areas that attract the most Government attention.

“Policy responses to PISA results differ from country to country, due to the complexity of each educational system. In studying the most influential factors affecting school performance, we offer new insight for policymakers to consider. Here in the UK, if any difference is to be made to school performance, it is clear that social policy rather than educational policy needs the most attention.”

Using direct comparisons in student performance from PISA test scores and questionnaires from school principals and students, researchers also found:

• In the UK, performance is impaired if the proportion of disadvantaged students in a school’s population reaches between 20-30 per cent. In the USA, to impact on performance, the percentage of disadvantaged students needs to reach 70-80 per cent.
• In some countries, the type of school students are in has a big bearing on individuals’ performance. In France, for example, almost 50% of the variability in student scores are down to the ‘school effect’. In Spain, though, students’ achievements are quite consistent throughout all schools which is evidence that certain educational policy aimed at schools will be more effective in some countries, than others.
• Parental education is a particularly relevant factor in Australia, Italy and Japan – with higher levels of parental education associated with better student achievement.
• The ratio of students to teachers has high influence in Canada, Japan and Spain but not elsewhere.
• Japan is the only country where self-motivation is the most important factor on student performance. If a student in Japan has less motivation than a certain threshold, no other factors will matter when predicting students’ achievement.

Chiara Masci, a PhD student from Politecnico di Milano, said: "Results show that school and student characteristics might have different impacts on school and student performances, depending on the context in which they act. Therefore, policy makers should take into consideration that acting on a particular aspect of the educational system might lead to different results, depending on all the other characteristics of the system."