A theory based on the mathematical notion that small changes in nonlinear systems can produce large and unpredictable results. Nonlinear systems react in complex ways to feedback. This extreme sensitivity to initial conditions is known as the butterfly effect (the idea that the flapping of a butterfly's wings in Asia may eventually alter the course of a hurricane in Florida). Chaos theory provides a theoretical frame-work for evaluators interested in holistic or systems analysis. Complex feedback processes take the place of linear cause-effect chains of events, emphasizing the examination of dynamic interrelationships among stakeholders and practices within social systems.