Table 1 Definition of realist terms used in this realist synthesis

Programme Theory

The often hidden assumptions about how an intervention works [37] that are contained within the literature on the intervention, for example, the assumptions of programme designers [39]. These are first identified from the literature as a series of ‘if…then…’ or explanatory accounts (EAs) [38] that are more or less explicit theories about what ‘what creates change’ [40]. These might later be ‘tested,’ developed, or overturned by primary research findings

Context

Situations and settings that ‘trigger’ particular mechanisms [41]. For example, Waldron et. al (2020) identify three significant contexts (pre-existing relationship; difficulty with decision; health system support) for SDM and identify these as impacting on all mechanisms. Their example highlights the practical limitations of available literature, albeit with stakeholder discussion [38]

Mechanism

Resources and relationships that produce a particular effect [42]. There are likely to be multiple and sometimes competing mechanisms within a single intervention [40]. No single study can identify all mechanisms or all aspects of a mechanism [36]. For example, anxiety, trust, perception of time, and self-efficacy are identified as key mechanism sets for SDM [38]

Outcomes

Effects of a mechanism that can be immediate or longer-term, of varying depth or duration, and impact on particular social groups in particular ways [38]. They might also be a conceptualised as a single outcome of a programme theory [38] or understood in terms of multiple, fluctuating outcomes [43]