Abstract
This guide provides an overview of using the Theory of Change (ToC) to assess social impact. Increasingly, public, private, and nongovernmental organisations are required to report the impact of their activities. This guide introduces the ToC, its origins, key building blocks, processes, and applications. It includes examples of best practices, case studies, and reflections to provide a foundational understanding of the ToC. This guide is suitable for corporate and voluntary sector leaders, funders, evaluators, educators, and students seeking to use the ToC for developing impact pathways and outcomes-based evaluations.