This guide is intended for policymakers interested in embarking on social
experimentation. It is divided into three sections.
(1) The first section briefly lays out some basic principles to follow in order to design
a potentially policy-relevant intervention, and illustrates these principles with an
(2) In the second section, the principles for six commonly used methods of evaluation
are presented. The methods are compared from the point of view of the reliability
of the results they deliver.
(3) The third section considers the costs associated with each method, and their
complexity to implement in practice.