This Study was commissioned by the OECD/DAC Expert Group on Aid Evaluation in October 1996 and completed in early April 1997. The agreed purpose was to undertake a synthesis study of NGO evaluations, supplemented where easily accessible with related data and information, in order to provide an analysis and assessment of the impact, including efficiency and effectiveness, of NGO development interventions, and to provide an analysis and assessment of evaluation methods and approaches used. Though NGOs are involved in a range of different activities, the major focus is on the impact of discrete projects, supplemented by some discussion of institutional and capacity-building initiatives. The Report has been compiled from two types of data sources: evaluation and related reports, dominated by donor-commissioned studies, and information gathered (through reports and interviews) from 13 country/donor case studies, which widened sources to include data from southern and northern NGOs and some community-based organisations (CBOs).