"Randomized experiments are increasingly used in development economics, with researchers now facing the question of not just whether to randomize, but how to do so. Pure random assignment guarantees that the treatment and control groups will have identical characteristics on average, but in any...

Many governments have spent much of the past decade trying to extend a helping hand to informal businesses by making it easier and cheaper for them to formalize. Much less effort has been devoted to raising the costs of remaining informal, through increasing enforcement of existing regulations....