Lay summary
New Zealand health policy has, since 2001, focused on improving access to and increasing the use of primary health care services, delivered ‘closer to home’, through new models of care, which emphasise better integration within health services and between health and social services. International evidence supports the general direction of health policy in New Zealand, suggesting that it should lead to improved health, reduced inequities in health, and lower health system costs. There are, however, major gaps in international knowledge about how health systems can successfully bring about such changes, and about what works for service users. This programme of research will use a realist approach, and, through five linked projects, demonstrate where and how successes are being achieved in Aotearoa/New Zealand, and identify where changes to policy and practice need to be made if we are to better achieve our health goals.