Peer Review

The economists (Xiadong Liu, Eleonora Patacchini and Yves Zenou, at least) are catching up with the world's parents);

Data has been collected on US students in grades 7-12 from a nationally representative sample of roughly 130 private and public schools in years 1994-95. The most interesting aspect of the data is the friendship information, which is based upon actual friend nominations. It is collected when individuals were at school where students were asked to identify their best friends from a school roster (up to five males and five females). As a result, one can reconstruct the whole geometric structure of the friendship networks.

We find that:

• For juvenile delinquency, students are mostly influenced by the aggregate activity of their friends (local-aggregate model).

This indicates important social-multiplier peer effects in delinquent activities.

• For education, both the social-multiplier and social-norm effects matter, even though the magnitude is higher for the social norm effect.

This indicates that students tend to conform to the social norm of their friends in terms of effort in education (local-average model).

As Thomas Sowell finds himself repeating in his numerous books, This may seem obvious, but...it is amazing how often the obvious is disregarded in public policy. The three economists spell it out;

The idea is to remove the criminal that reduces total crime in a network the most ....the removal of the key player can have large effects on crime because of the feedback effects or ‘social multipliers’ at work. As the fraction of individuals participating in a criminal behaviour increases, the impact on others is multiplied through social networks.

Keep away from bad companions, kids!

For education policy, our results show that the local-average model is at work. This suggests that one should change the social norm in the school or the classroom. One should try to implement the idea that it is ‘cool’ to work hard at school.

An example of a policy that has tried to change the social norm of students in terms of education is the charter-school policy. The charter schools are very good in screening teachers and at selecting the best ones. In particular, the ‘No Excuses policy’ (Angrist et al. 2010, 2012) is a highly standardised and widely replicated charter model that features a long school day, an extended school year, selective teacher hiring, strict behaviour norms, and emphasises traditional reading and math skills.

The main objective of these policies is to change the social norms of disadvantage kids by being very strict on discipline. This is a typical policy that is in accordance with the local-average model since its aim is to change the social norm of students in terms of education. 

Another way to do that is to allow parents to easily remove their children from dysfunctional schools and deny those schools taxpayer funds.

As William of Occam knew, the best ideas are usually the simplest ideas.