Primary care is currently at the heart of the National Health Service policy. The newly established organisations, known as Primary Care Groups and Trusts (PCG/Ts), have the crucial role of improving the efficiency and equity in primary care delivery. However, not many studies have focused on performance assessment in primary care provision. In this thesis we aim to contribute to a discussion regarding appropriate ways to compare the performance of primary care providers and the effective ways to use these results in order to improve performance in primary care. Following a review of the literature, a conceptual framework for performance assessment in primary care was developed in collaboration with a sample of PCG/Ts. This framework aims to establish a link between the local needs, the resources used, the services delivered and the outcomes achieved in primary care. Based on the relationships between these elements, four performance assessment criteria were defined: equity, efficiency, service effectiveness and cost effectiveness. DEA is then proposed to measure efficiency, service effectiveness and cost effectiveness, given the fact that it can handle multiple inputs and outputs without requiring the specification of a functional form. Following the Government’s policy of focusing on the management of chronic diseases, this conceptual framework is then applied to compare the performance of a sample of GP surgeries in terms of their delivery of diabetes care. An exploratory and formative comparison is undertaken in order to investigate why certain surgeries appear to perform better than others, and in order to identify ways in which some of the surgeries can improve their performance. The relationships between the different performance criteria are also investigated, together with the ways in which an adequate balance between the different criteria can be achieved. Several conclusions are arrived at and several contributions arc made to this research area. The usefulness of complementing efficiency analysis with equity and effectiveness analysis; the usefulness of following a formative methodology in the use of DEA; the importance of estimating the costs involved in achieving speciality based outcomes; the importance of area deprivation in the achievement of effectiveness and the limitations of the data available in primary care in England.