In total, 118 documents (see Fig. 2 for details on how they were located and Additional file 4: Table of studies coded in the review) were coded to develop CMOCs that were used to refine and expand our initial programme theory. They were published between 1992 and 2019, covering projects run in the south, midlands and north of England, as well as Scotland, Wales and Northern Ireland. As illustrated in Fig. 3, most documents used to develop CMOCs could be classed as ‘grey literature’, coming from evaluations and reports.
In this section, we provide a narrative overview of the two key concepts underpinning our final programme theory. It is based on the initial 29 CMOCs we developed (see Additional file 3: CMOCs for programme theory refinement, with data extracts) from the reviewed literature.
Concept 1: Creating and sustaining ‘buy-in’
Social prescribing connector roles are relatively new to the NHS. ‘Buy-in’ to this type of service and people delivering it is the important first step to producing intended outcomes. This relates to legitimising the service and a belief in individuals undertaking this role.
Legitimising the service
Key stakeholders (e.g. patients, GPs, commissioners, primary care staff) must ‘buy-in’ to the social prescribing connector role as a judicious route to addressing ‘non-medical’ needs; otherwise, the service may be dismissed by patients as a means of blocking them from seeing their GP, and by healthcare professionals (HCPs) as another ‘gimmick’ (a danger if funding is short-term and the service is branded as a pilot). Acceptance may be engendered through the endorsement of such provision by credible sources. For example, HCPs may hear about a service in glowing terms from respected colleagues or those in a leadership role. ‘Buy-in’ may be exhibited in a practice setting by senior staff making space for a link worker (e.g. providing them with a room to see patients, giving them access to tea/coffee making facilities).
Patients may view link workers favourably after discussing the role with a trusted GP, whose referral validates the service. However, it may be necessary for patients to be at a stage in life when they have the energy and mental capacity to ‘buy-in’ to a new way of addressing their problems. This may not be possible if psychosocial difficulties (e.g. family complications or poor mental health) are perceived as overwhelming. Not having to wait to see a link worker is also crucial, to prevent a patient losing momentum in seeking assistance.
Clear information about the role and remit of link workers should avoid misunderstandings and unrealistic expectations. Patients may be deterred from seeing a link worker if they believe this is part of formal social services, regard referral as stigmatising or feel that their situation requires medical intervention. Making time to explain the service to HCPs and patients (e.g. in face-to-face meetings, via accessible leaflets) is therefore important. Likewise, incorporating processes (e.g. referrals) into existing systems within a surgery (e.g. linking it to current IT platforms) will encourage HCPs to see the service as easy to use. Consulting with key stakeholders from the outset could increase the chance of social prescribing connector roles being developed in a manner that helps rather than hinders current practice.
Members of the VCS must ‘buy-in’ to the idea of a social prescribing connector role, believing they will receive appropriate referrals and that demand for their services will remain manageable. The VCS should be involved in initial discussions about setting up a connector scheme, to forestall concerns and to ensure those working in this arena feel like valued partners—thereby helping to foster ‘buy-in’.
Belief in an individual link worker
Key stakeholders must ‘buy-in’ to the skills and knowledge of individual link workers. HCPs need to regard them as credible and competent before forwarding referrals. This can be achieved through receiving regular feedback about how a link worker is helping patients. Positive feedback creates confidence in the link worker. A feedback loop may then be established, increasing HCPs’ trust in this individual, so they make more referrals.
Patients must believe they will benefit from seeing a link worker. For this to occur requires link workers with the skills, attitude and time to encourage patients to open up, who demonstrate a genuine wish to help by offering personalised support. They may start by working on simpler difficulties to resolve (e.g. arranging for mobility equipment to be installed into someone’s home), before tackling more challenging issues (e.g. social isolation following bereavement), so that patients lacking motivation to change are not discouraged and to enable people to experience incremental successes. Link workers may need prolonged engagement with a patient to work in this way. The service is at risk of dilution if the workload is too great; this could prevent link workers from thinking creatively about how best to support individuals and from establishing connections within the VCS, which is important for ‘buy-in’ to an individual link worker’s credibility.
Concept 2: Establishing and maintaining connections
‘Buy-in’ is a first, essential step in establishing a social prescribing connector scheme and ensuring that patients are willing to try it. A further issue is ongoing inter-relations. This starts when trying to secure the ‘buy-in’ of stakeholders but warrants further consideration, as once the service has been accepted as a viable option, its success rests on sustained, strong connections between the link worker and other key stakeholders.
Giving life meaning and inspiring hope
The ‘buy-in’ referred to above results in a patient who is prepared to listen to what a link worker proposes. Link workers give people permission to consider and prioritise their needs and legitimises the accessing of support from others. They can help lessen the mental load associated with change by developing an action plan with the patient. Feeling safe to disclose potentially sensitive information to a link worker may be a stage that patients have to pass through; ongoing conversations allow trust to be iteratively built and reinforced, prompting patients to try new activities or to seek external help. Patients may consider, with the link worker, ways of resolving potential barriers (e.g. due to travel, childcare). This enables them to move forward in life, becoming connected to community resources, so they feel less isolated and more in control of their situation. Making new connections through the link worker can result in patients no longer fixating on personal problems. There is a danger of patients becoming dependent on a link worker as the source of support; this should be tempered if individuals create new and meaningful connections within the community, which may include reconnecting with friends and family because of a more positive outlook on life. Such an improved outlook may encourage those with existing health conditions to actively engage in self-care.
Integrating health and community assets
Link workers were depicted in some reviewed literature as fostering better connections between HCPs and the VCS. It was noted that the former can be sceptical and unsure about the latter’s ability to help patients. In addition, VCS staff can feel that access to communicate with HCPs is challenging. Link workers undertake a brokerage role, having time to foster relationships within each setting and understanding the culture and language associated with primary care and the VCS. They can forge links by organising joint events, or they may produce feedback about patients’ progress that is shared with both groups. This raises awareness of the work and input of each party in addressing patients’ needs, increasing mutual respect. HCPs can feel less frustrated when managing patients with ‘non-medical’ problems, if a link worker highlights options available in the VCS.
Supporting the supporter
For link workers to continue acting as a credible source of assistance for patients, they should receive appropriate training (e.g. in active listening, being non-judgmental, motivational techniques). An environment offering supervision or peer support allows anxieties or difficulties associated with the role to be shared and explored. Problems arise when the link worker’s capacity and capabilities are overextended, especially if HCPs refer complex cases because (a) they believe the link worker can cope and (b) there is a lack of immediately accessible alternatives (due to long waiting lists for statutory services). The link worker may become so overstretched that they leave their post. When a link worker leaves, they take with them tacit knowledge of local, reliable VCS providers, and relational links. Consequently, improvements made by the service may temporarily decline as a new link worker is installed and has to create positive connections with a range of stakeholders.
Intermediate programme theory (prior to considering existing, substantive theories)
Figure 4 brings together the broad concepts described above into an intermediate programme theory. It illustrates how ‘buy-in’ allows for connection. ‘Buy-in’ is required initially; otherwise, connections will not be made and cemented. Connection involves building and sustaining productive working relationships. In the figure, there is overlap between service and individual ‘buy-in’ because belief in someone delivering a social prescribing connector role may strengthen stakeholders’ belief in the service, or their ‘buy-in’ to the rationale behind the service prompts them to support an individual connector’s work. Within the programme theory, a cultural change in avenues considered acceptable for addressing health and well-being may be required from stakeholders for ‘buy-in’ to transpire. Hence, time and energy should be invested, upfront, in promoting the service to all key stakeholders as complementing medical care; otherwise, the development of trust and associated connections may be hindered.
Contribution of existing theory
As noted in the methods section, we further refined and organised our understanding of social prescribing connector roles by drawing on two existing theories; they were selected from theories mentioned in reviewed documents that we felt were particularly pertinent in explaining key elements of our programme theory. Based on our interpretation of the data from the review, we inferred that through developing ‘buy-in’ and strong relational connections, link workers mobilise resources that come from being part of social networks. We propose that these networks then prompt patients to feel more able and willing to manage their own health goals. Therefore, the existing theories we drew upon were social capital and patient activation.
Social capital refers to the resources accrued from connections . Putnam  identified two key forms of social capital:
Bonding—close-knit networks that produce feelings of solidarity and reciprocity. It involves links with like-minded people, with some form of shared identity.
Bridging—these ties tend to be weaker, more fragile, with less emotional closeness, but can be useful for gaining information or developing a new perspective as it means being part of a heterogeneous grouping.
In terms of connector schemes, bonding social capital could occur when colleagues support each other with problem-solving and managing difficult emotions; trust is necessary for this situation for link workers to voice concerns to their peers. It also relates to the connection between patient and link worker; the latter takes time to get to know the former’s situation, develops with them a personalised action plan and, depending on the patient, offers emotional support. Such bonding social capital may make patients feel safe to open up to a link worker. However, bonding social capital can entail some form of exclusion, only benefitting those with access to a network/group. This is how providers in the VCS sometimes described their experience of trying to make links with HCPs. When trust between these two groups is lacking, the link worker takes on a bridging role, forging a closer relationship between the VCS and HCPs. Bridging social capital can also be identified when link workers connect patients to organisations or activities where they meet people from outside their direct social sphere. This enables them to gain information or a fresh perspective and to cultivate new skills.
Bourdieu  is another key writer on social capital. His work focused on resources derived by an individual from social networks to pursue their goals. For Bourdieu, such networks and their benefits do not occur naturally, but call for input (time and symbolic exchange); from this perspective, social capital represents an intentional process and ongoing investment in anticipation of future dividends . This relates to the need for time and resources upfront in establishing social prescribing connector schemes as a new way of working within healthcare.
Carpiano  integrated conceptualisations of social capital from Putnam and Bourdieu into the following schema, which underpinned our understanding of how it relates to social prescribing connector roles:
Structural antecedents—structural forces have implications for the type and strength of social ties that can be drawn upon. In social prescribing, a vibrant VCS is required. Furthermore, link workers need time to develop up-to-date knowledge of local, quality VCS provision and should be supported in this role through supervision and training. Another antecedent is the importance of consulting with key stakeholders to ensure that any service can fit into existing primary care systems and to overcome potential accessibility issues (e.g. due to transport or disability). In our review, there also seemed to be ‘personal antecedents’ (e.g. the patient being at a place in life when able to contemplate making change). Overall, this is about providing the right foundations for trust in link workers to blossom.
Social cohesion—trust in link workers forms a basis for connections to be developed, from which social capital can transpire. This may occur incrementally. It covers the idea of link workers facilitating interactions between the VCS and HCPs; a better appreciation by HCPs of the former means those running VCS services are brought into conversations about health and well-being. It also relates to the time and consistency called for in interactions between a patient and link worker.
Social capital—resources that stem from social connections. When working with a link worker, these resources may be cognitive (e.g. trusting others, appreciating community assets), psychological (e.g. self-confidence, self-control, belonging) and instrumental (e.g. having contacts to draw on for practical support or advice).
Outcomes—developing social capital (in its various guises) could increase a patient’s sense of well-being. As individuals feel more socially included and self-confident through joining groups and receiving helpful outside advice, they become less reliant on their GP. Alternatively, a strong connection with the link worker means the patient feels safe to disclose difficulties that then need input from a GP.
Patient activation is defined as people’s confidence, motivation and ability (skills/knowledge) to manage their health . Patient activation brings into focus attitudes and beliefs as well as behaviours and knowledge . The problem, according to Hibbard , is many providers just give patients information without understanding where they are in terms of believing they can control their health situation. This may be unsuccessful in assisting individuals with low activation levels, as they can feel overwhelmed by and have limited confidence in managing their health . It is argued that by tailoring an intervention to someone’s activation levels, they are more likely to encounter small successes, which propels them forward rather than leaving them deterred due to a lack of achievement .
A patient activation measure (PAM) has been developed to gauge how motivated and able someone is to manage their health [30, 31]. People identified as activated on this measure appear more likely to adopt healthy behaviours (e.g. diet and exercise) and to have less hospital use . Intervention components linked to increasing patient activation scores include those that help with skills development, problem-solving, peer support or engender change in beliefs and social norms . Link workers can cover these components (e.g. encouraging patients to think of assets and solutions to their problems when co-producing an action plan, linking them to networks that can foster connections). Through feeling more activated, a patient may be motivated to invest in self-care, prompting them to visit a GP for advice.
Bringing existing theories into our programme theory
From reviewed literature, we have used abductive reasoning (i.e. making judgements about which theories provide the best and simplest explanations) to detail how social capital and patient activation relate to social prescribing connector roles. We argue that gains from increased social capital include reduced isolation, feeling that life has meaning and having a support system that can be consulted for advice. This transformation prompts someone to be more activated in terms of their ‘internal readiness and capabilities to undertake health-promoting actions’ .
Table 3 outlines a list of CMOCs we developed following further interpretation of our data through the theoretical lenses of social capital and patient activation (see Additional file 5: Final refined realist analysis, with supporting extracts from included papers). They build on the CMOCs we created for our intermediate programme theory (see Additional file 3: CMOCs for programme theory refinement, with data extracts). As illustrated in Fig. 5, our ‘final’ refined high-level programme theory shows that those likely to benefit from seeing a link worker are patients able to change their outlook on life, who can build and sustain their social capital. This may only happen when motivation and engagement are present. Feeling better connected and accruing resources from this (e.g. trusting in others, increased confidence, having people to access for assistance) may augment an individual’s activation to meet their health and well-being goals. Some patients are liable to find it relatively easy to make social contacts and move forwards. Others may require encouragement and direction from the link worker. It should be borne in mind that not all patients will be comfortable forging greater ties with outside groups or organisations. Hence, although accessing external support may enable patients to feel less alone or focused on their personal struggles, and/or bring hope of solutions to their problems, this will only work if someone deems that this is applicable to their circumstances. They also need to be able to access local assets that can address their needs; not all parts of the country may have a vibrant VCS to allow for this to happen. For the benefits from social prescribing to accrue, patients must be open to engaging with activities or accessing services (buy-in) and willing to make connections. Those who resist such external affiliation may not gain as much from seeing a link worker. There may be other patients reporting emotional solace from meeting with a link worker who still needs support from HCPs due to the complexity of their health condition.