Four suppositions about emergent properties of complex interventions that operate and function as systems: A call for evaluation research

This article focuses on evaluating the emergent properties of complex interventions that operate and function as systems. After defining key terms, four suppositions of emergence are presented. The suppositions are based on the authors’ reflections on evaluating several complex interventions using a systems approach. Supposition 1 posits that there is an operational emergent property, paralleling the theory-driven evaluation concept of implementation theory noted by Carol Weiss. Supposition 2 suggests that every complex intervention also has a functional emergent property that speaks to the effectiveness of the intervention. Several important distinctions between a functional emergent property and the long-term outcomes derived based on a reductionist worldview are noted. Supposition 3 builds on the work of Chalmers to posit that it is possible for a complex intervention to simultaneously have more than one operational emergent property and more than one functional emergent property. Supposition 4 is grounded in the system definition to propose that operational emergence is a prerequisite for functional emergence. Suppositions by definition require proof to become theories. The article calls for evaluators to share whether their experiences support these suppositions and encourages investments in evaluation research to test them.