To identify and understand which theories could explain how reminder intervention work|
Jagosh et al. 2011 defines middle-range theories as when the theory can retrain its relevance across multiple cases and different context. Thus, it cannot be abstract to the extent that it is disconnected to the actual working of a program, neither can it be so specific that it is only relevant to one case .
To evaluate whether a reminder system increases women’s participation in screening (O), a realist would examine and try to understand the underlying mechanism (M) (e.g., information, advice, trust, engagement, motivation) and its contiguous context (C) (e.g., demographics, legislation, culture norms)  These interactions and relations are defined as Context-Mechanism-Outcome (CMO-configurations) [17–19]|
Dalkin et al. 2015, operationalizes the CMO-configurations (CMOc) formula where intervention resources are introduced in a context in a way that enhances a change in reasoning 
|Social ecological theory||
Applying the social ecological theory can provide a framework to increase understanding of a human’s interaction with their physical and sociocultural environments and thereby also the environment’s influence on their reasoning regarding an intervention |
A social ecological theory could be defined as is integration of person-focused programs with environment-focused initiatives to strengthen physical and social surroundings