Table 1 Glossary of Terms

Realism: The philosophy of realism brings attention to the limits of both logical empiricism which obfuscates the active theorizing of unobservable agents of causation (e.g., as demonstrated through the logic of randomized controlled trials) and constructivism which negates the belief of universal laws in favor of comparing storylines and paradigms. Realist modes of research reflect a mix of these two approaches by posing the kinds of questions that seek out the truth of matters, while at the same time operating from a view of the context bound and contingent nature of human knowledge.

Realist Review (RR): is a theory-driven approach to synthesizing quantitative, qualitative or mixed methods research, from a perspective based in Realism. It answers questions of the general format ‘what worked, for whom and in what circumstances, how and why?’ The basis of a realist causal explanation is Context + Mechanism = Outcome (Otherwise referred to as the CMO configuration)

Middle-range theory (MRT): Middle-range theory is an implicit or explicit theory that can used to explain the cause of outcomes for programs and interventions or parts thereof. “Middle- range” means that the theory can be tested with the observable data and is not abstract to the point of addressing larger social or cultural forces (i.e., grand theories) [1]. MRT is formulated at the outset of a realist review and examined in relation to empirical evidence throughout the review process.

Context-mechanism-outcome (CMO) configurations: CMO configuring is a heuristic used to generate causative explanations pertaining to outcomes in the observed data. The process draws out and reflects on the relationship of context, mechanism, and outcome of interest in a particular program. A CMO configuration may pertain either to the whole program or only to certain aspects.

Context: Context often pertains to the “backdrop” of programs and research. As conditions change over time, the context may reflect aspects of those changes while the program is implemented. Examples of context include cultural norms and history of the community in which a program is implemented, the nature and scope of existing social networks, or built program infrastructure. They can also be trust-building processes, geographic location (e.g., rural or urban), types of funding sources, and other opportunities or constraints.

Mechanism: A mechanism is the generative force that leads to outcomes. It typically denotes the reasoning (cognitive or emotional) of the various actors in relation to the work, challenges, and successes of the partnership. Mechanisms are linked to, but not synonymous with, the program’s strategies (e.g., a strategy may be an intended plan of action, whereas a mechanism involves the participants’ reaction or response to the intentional offer of incentives or resources). Identifying the mechanisms advances the synthesis beyond describing “what happened” to theorizing “why it happened, for whom, and under what circumstances.”

Outcomes: Outcomes are either intended or unintended and can be proximal, intermediate, or final. Examples of intervention outcomes are improved health status, increased use or quality of health services, or enhanced research results.

Demi-regularity: Demi-regularity means semi-predictable patterns or pathways of program functioning. The term was coined by Lawson, who argued that human choice or agency manifests in a semi-predictable manner—“semi” because variations in patterns of behavior can be attributed partly to contextual differences from one setting to another [2].