Introduction: A key component of achieving integrated care for patients is to improve use of health providers by reorienting models of care. Developing advanced practitioner roles, as part of workforce redesign, offers potential solutions to burgeoning demands on health systems. In New Zealand, original policy objectives for advanced practitioner roles sought improved quality of patient care and service access. Currently, the uptake of training and employment of nurse practitioners and pharmacist prescribers (advanced practitioners) is not meeting policy makers’ expectations. New Zealand-specific research on advanced practitioner role development is limited, making informed implementation of these roles difficult. This research offers the first rigorous evaluation of New Zealand nurse practitioner and pharmacist prescriber development in primary health care to inform better policy and practice decisions. This presentation focusses on contextual factors within policy and practice that affect the development of advanced practitioner roles. Theory/ Methods: This research follows a realist evaluation methodology. Realist evaluations generate, test, and refine theories of how programmes work within contextual constraints. This research involves semi-structured interviews with policy and training stakeholders, nurse practitioners, pharmacist prescribers, general practitioners, and patients. Further information supporting these interviews derives from (1) reviews of documents on specific advanced practitioner roles and (2) field notes. Results: Key contextual factors (such as funding, legislation, and responsiveness to change) affecting advanced practitioner role development exist within three domains: (1) policy creation, (2) role creation, and (3) role realisation. Preliminary results are that in each of these domains there is poor understanding and recognition of these advanced roles. This has negatively affected practitioner training uptake and their employment as advanced practitioners. Discussions: This research examines processes by which nurse practitioner and pharmacist prescriber roles evolve within the complex and ever-changing New Zealand health system. Informed health professional deployment needs to take into account the impact context has on policy creation, role creation, and role realisation. Conclusions: Advanced practitioners operate in environments ill-equipped to gain full benefit from their employment. Improved understanding of their roles, funding supporting policy, and recognition by patients and health professions, can enhance role clarity, reduce legislative and operational barriers, and improve service delivery. This research widens the traditional health system focus to include factors influencing effective, efficient, and sustainable integrated care. Lessons learned: Effective health workforce redesign requires an appreciation of the interaction of many factors. Recognition of these influences may localise a problem and facilitate dialogue, furthering employment of all health professionals, and subsequently improving workforce skill-mix. Significant challenges remain in effectively developing advanced practitioner roles; these are outlined along with suggestions for tackling them. Limitations: Theories formulated from this research may require modification to reflect country-specific needs and resources. Suggestions for future research: Developing new health professional roles often occurs without evaluating the impact these roles have on patients or providers. Further research will improve clarity in role definitions and skill-mixes, leading to enhanced integration and realisation of practitioner potential. This should improve both quality and continuity of care for patients.