Measuring the iceberg: complex lives, invisible metrics, and lived experience in social prescribing.

Introduction: Social prescribing has emerged as a prominent public health intervention in the UK and internationally, intended to address non-medical determinants of health and reduce pressure on healthcare systems. Despite its rapid expansion, the evidence base underpinning social prescribing remains contested. Dominant evaluation frameworks tend to prioritise quantitative indicators such as referral volumes, attendance rates, changes in standardised wellbeing scores, and short-term service utilisation. While these measures provide policymakers and commissioners with familiar forms of evidence, they often fail to capture the forms of change participants themselves describe as most meaningful. Methods: This study uses the metaphor of the iceberg as a critical analytic lens to examine what remains invisible within prevailing evaluation regimes. Drawing on forty in-depth qualitative interviews with individuals engaged in social prescribing, the study explores experiences of referral, engagement, perceived impact, and the role of link workers in supporting participation. Thematic analysis focused on how participants interpreted social prescribing within the broader context of their lives and how this shaped engagement and perceived outcomes. Results: Three interconnected themes emerged. First, engagement frequently occurred against a backdrop of cumulative and overlapping life struggles, including trauma, chronic illness, poverty, social isolation, and experiences of systemic exclusion. Second, participants described profound and often unexpected forms of change that extended beyond standard wellbeing outcomes, including increased feelings of safety, restored trust, renewed purpose, and the prevention of further deterioration or crisis. Third, the relational labour of link workers was central to enabling engagement and sustaining fragile forms of progress over time. Discussion: By foregrounding lived experience, the findings challenge reductionist models of evidence and suggest the need for a recalibration of how social prescribing is evaluated. The study highlights the importance of recognising stabilisation, prevention, and relational processes as legitimate forms of impact, which are currently underrepresented in the evidence informing public health policy, commissioning, and practice.