Development and evaluation of complex interventions in health services research: Case study of the Southampton heart integrated care project (SHIP)
Interventions are often defined pragmatically and lack any clear theoretical basis, which limits generalisability. Implementation is rarely described, which limits understanding of why an intervention is or is not locally successful. Integration of qualitative methods within pilot trials can help interpret the quantitative result by clarifying process and testing theory. This approach defines three levels of understanding: the evidence and theory which inform the intervention, the tasks and processes involved in applying the theoretical principles, and people with whom, and context within which, the intervention is operationalised. A case study shows how this novel method of programme development and evaluation can be applied.