the evaluations of community change initiatives. In the years that followed, a number of evaluations were developed around this approach, fueling more interest in the field about its value and potential application. Between 2000 – 2002, the Aspen Roundtable for Community Change led the dissemination and case studies of the Theory of Change approach, although still mostly applied to the field of community initiatives. As the Aspen Roundtable concluded its leadership in the field and moved on to apply Theory of Change to such topics as structural racism, others expanded the visibility and application of Theory of Change into international development, public health, human rights and more. The visibility and knowledge of Theory of Change grew with the creation in 2002 of theoryofchange.org and later of Theory of Change Online software. Growing popularity Recent interest has burgeoned with some excellent reviews commissioned by Comic Relief in the UK, the Department for International Development in the UK, the Asia Foundation and Oxfam Australia to name a few. The explosion of knowledge of the term, and demand for "theories", led to the formation in 2013 of the first non-profit dedicated to promoting and clarifying standards for Theory of Change. The Center for Theory of Change houses a library, definitions, glossary and is licensed to offer Theory of Change Online by ActKnowledge free of charge. The use of Theory of Change in planning and evaluation has increased among philanthropies, government agencies, development organizations, universities, international NGOs, the UN, and many other major organizations in both developed and developing countries. This has led to new areas of work, such as linking the Theory of Change approach to systems thinking and complexity. Change processes are no longer seen as linear, but as having many feedback loops that need to be understood. Consequently, Theory of Change is strengthening monitoring, evaluation and learning. They are also helping to understand and assess impact in hard to measure areas, such as governance, capacity strengthening and institutional development. Innovations continue to emerge. Challenges Despite the growing ubiquity of Theory of Change, especially in the development arena, understanding of the approach and the methods necessary to implement it effectively are not uniform. In fact, there is evidence of some confusion about what the term ‘Theory of Change’ actually means; in some cases, what some program developers describe as a Theory of Change is, in essence, simply a log frame, strategic plan