People act on the basis of their understanding of how the world works – their ‘theories of action’. We do X because we believe, based on past experience or what we’ve read, that Y will happen. This applies to projects and programs as well. So it follows that if you can improve a project’s theories of action you can improve how people implement it (project is used here to mean both project and program). This has long been recognized by a particular branch of evaluation, called program theory evaluation, which describes projects’ theories of action in a ‘logic model’ and then evaluates the project using the model as a framework.