This report is a user's guide for defining, measuring, and improving the performance of health service delivery organizations. The authors define six core performance domains: quality, efficiency, utilization, access, learning, and sustainability and provide a compendium of metrics that have been used to measure organizational performance in each of these six domains. The compendium, which includes 116 distinct categories of metrics, is based on a detailed literature review of peer-reviewed empirical studies of health care organizational performance in World Bank client countries. Based on reading of the literature, the authors define seven major strategy areas potentially useful for improving performance among health care organizations: 1) standards and guidelines, 2) organizational design, 3) education and training, 4) process improvement and technology and tool development, 5) incentives, 6) organizational culture, and 7) leadership and management. The authors provide illustrations of facility-level interventions within each of the strategy areas and highlight the conditions under which certain strategies may be more effective than others. The authors propose that the choice of strategy targeted at organizational level to improve performance should be informed by the identified root causes of the problem, the implementation capabilities of the organization, and the environmental conditions faced by the organization.