The number of friends you have at school can affect your educational achievement – but the precise outcomes depend on the type of relationships you have and the social background of your friends. This is the main conclusion of new research by Victor Lavy and Edith Sand, published in the January 2019 issue of The Economic Journal.
To investigate the extent to which students’ social relationships affect their grades, the authors consider the impact of separating students in Israel during their transition from elementary to middle school at the age of 12. They find that maintaining your social circle in class during this transition can improve your exam results in the eighth grade at the age of 13.
The authors also find that this gain in academic results might be partly brought about through greater cooperation, reductions in violent behaviour and improvements in social satisfaction in class.
The study uses students’ own definition of friendship and the random assignment of students to classes to understand their effects. According to the researchers, this impact has important economic consequences for students because they determine their admission to different fields of study and, to a larger extent, their future earnings.
It also highlights the consequences of policies that separate students from their social networks. For example, the authors point out, that housing programmes and school choice have a small or no effect on the educational outcomes of poorer students.
The authors argue that the possible negative consequences on students’ education and behaviour of separating them from their social network is not considered in policy-making. There are many educational policies and practices that separate students, including school integration and choice of schools as well as social and welfare programmes such as the US Moving to Opportunity. They conclude that taking account of the consequences of keeping social networks intact can improve how policies are designed.
'The Effect of Social Networks on Students' Academic and Non?cognitive Behavioural Outcomes: Evidence from Conditional Random Assignment of Friends in School' by Victor Lavy and Edith Sands in published in the January 2019 edition of The Economic Journal.

Victor Lavy
professor of economics at University of Warwick and the Hebrew University of Jerusalem