The increased prevalence of chronic disease offers nurses the challenge of providing educational interventions for people living and managing a condition such as diabetes mellitus. This article uses theoretical models and approaches from health promotion to offer perspectives to explain behaviour and determinants of health. The competing needs and perspectives are applied to see their relevance within diabetes nursing care, and in particular when looking at patient outcomes for a group intervention, raising the question: what is an effective intervention? Evaluating interventions needs clear identifiable values and aims, although this article highlights that success of any intervention will mean different things for the participant or health professional. There is a need for research into the subjective experiences of people with diabetes managing an intensive insulin regimen, and to value and include a wider definition of evidence-based outcomes.