Brazil fact of the day

In Brazil, they segregate their prisons according to gang membership.
No exceptions. Not even for individuals who in fact are not members of
any gang.

How does that work?  Easy.  Upon being admitted to the prison system, unaffiliated prisoners are required to join a gang.

Here is more, from Amanda Taub.  Here is her blog.  Here is another new economics blog, on models and agents.