"Theory of change is actually a very simple concept. Throughout our work and personal lives we have aims, objectives and ideas about how to achieve our goals, but we rarely take the time to think these through, articulate and scrutinise them. All a theory of change process does is to make these assumptions explicit and therefore more testable. While the idea itself is simple, the terminology around theory of change can be confusing because there are variations in the approach. In this document we use the term to refer to the broad family of approaches that all help to articulate the reasoning behind a project. This includes the CES Planning Triangle©, logic models, outcomes chains, and narratives. However, others in the field use theory of change to refer only to the outcomes chain approach. As an organisation thinking about using theory of change, the most important thing is not to get bogged down in terminology, but to use the method that suits your needs best. This guide aims to help you through your theory of change process and support you to produce something that strengthens the design and delivery of your projects, and gives you confidence in your approach to evaluation and learning." (Introduction)