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Table 1 Glossary of terms


Term Definition
Realist review A theory-driven approach to synthesising secondary research (including quantitative, qualitative, or mixed methods research). It aims to develop an explanatory model for how a programme (or different programmes) bring about a recorded change, why, for whom, and under what circumstances. It does this by developing realist programme theory, expressed as Context + Mechanism (Resource/Response) = Outcome.
Rapid-realist review (RRR) An adapted form of realist review, which provides a truncated method for the development of realist programme theory, whilst preserving the core elements of realist methodology. It relies more explicitly on stakeholders to focus and expedite the review process.
Programme theory An explanation for how a programme works. Realist reviews and RRRs attempt to develop and test programme theory.
Provisional programme theory A hypothesised explanation for how a programme is expected to work. Realist reviews and RRR usually start by developing a provisional programme theory to be tested using the literature.
Refined programme theory The product of a realist review or RRR. An explanation for how a programme works in practice, based on empirical data identified by the review.
Context-mechanism-outcome (CMO) configuration A heuristic used in realist reviews or RRRs to structure an explanation for how a programme, or part of a programme, works. CMO configurations act as the building blocks for programme theory.
Context Covers the programme context and the broader contextual backdrop that the programme is situated within, which modify the expression of mechanisms [22].
Mechanism The “underlying entities, processes or social structures, which operate in particular contexts to generate outcomes of interest” [18]. This review focused on the individual reasoning and preference construction, which occurred in response to resources implemented by the opt-out testing programme [79].
Outcome Both the intended and unintended consequences of the opt-out testing programme. Outcomes can be proximal, intermediate, or final [22].
Nudge Theory Nudge is a “substantive theory” (i.e. a theory that exists within a discipline, which can be used to help understand the way a programme works). Utilised in the fields of behavioural science and economics, it describes various quirks of human behaviour and decision-making and suggests ways these can be used to encourage certain actions.
Default Effect A theory within Nudge, which suggests that for any choice or action, there is a tendency for the majority of individuals to stick with the default option.