This article from Tom Ling outlines the use of uncertainty and complexity in a Theory of Change-based approach to evaluating complex interventions.
"This article discusses an approach to managing the evaluation of complex interventions. Complex interventions pose significant challenges to the role and conduct of evaluations. In particular, they combine with reflexive learning and change to produce significant uncertainties making it hard to describe in advance what the intervention will do or what the outcomes might be. These uncertainties vary in nature and addressing these uncertainties leads to different evaluation approaches. That such evaluations often take place in ‘real time’ and have a strong formative dimension adds to the challenge. This article proposes a way of approaching this problem by incorporating the concepts of uncertainty and complexity into a Theory of Change-based approach" (Ling 2012)