Assessing the health benefits of advice services: using research evidence and logic model methods to explore complex pathways.

Poverty is positively associated with poor health; thus, some healthcare commissioners in the UK have pioneered the introduction of advice services in health service locations. Previous systematic reviews have found little direct evidence for a causal relationship between the provision of advice and physical health and limited evidence for mental health improvement. This paper reports a study using a broader range of types of research evidence to construct a conceptual (logic) model of the wider evidence underpinning potential (rather than only proven) causal pathways between the provision of advice services and improvements in health. Data and discussion from 87 documents were used to construct a model describing interventions, primary outcomes, secondary and tertiary outcomes following advice interventions. The model portrays complex causal pathways between the intervention and various health outcomes; it also indicates the level of evidence for each pathway. It can be used to inform the development of research designed to evaluate the pathways between interventions and health outcomes, which will determine the impact on health outcomes and may explain inconsistencies in previous research findings. It may also be useful to commissioners and practitioners in making decisions regarding development and commissioning of advice services.