International comparisons are an important tool for benchmarking health system performance, shedding light on health systems' relative strengths and weaknesses. The present work examines how different groups of countries sharing similar health system characteristics perform relative to others. To make valid and useful comparisons, health systems may be grouped in ways that resonate with policy makers in countries and reflect the policy question at hand. The report specifically addresses three key policy areas: the influence of the overall design of health systems on performance, the role of financial incentives to providers and the role of a strong primary care system. The report shows that there is no indication that any one group of health systems would systematically outperform another. It further provides evidence that there is room for health systems sharing the same broad characteristics to improve performance by borrowing elements from other systems. Rather than engaging in large-scale system reforms, focusing on more targeted policy changes may be a better avenue for improving performance.