A working guide to international comparisons of health

Comparisons of health between countries are popular and useful, and often attract media attention. This guide highlights the types of questions to ask before comparing countries and when presenting health data in an international context. Summary Why are international health comparisons so popular? We are often interested to see how our national experiences of health and health care compare on an international scale. These comparisons create a broader perspective for researchers, policy makers and the general public. Being aware of the successes and setbacks of other countries may inform how new policies, health interventions or preventative measures are developed and implemented in one’s own country. International health comparisons can attract media attention, particularly if attempts are made to rank countries by performance. However, making valid comparisons of health across different countries is not always easy. International comparisons can be complex Both the use and interpretation of international comparisons need to be considered carefully. If the data and methods that underlie these comparisons are not assessed, the results could be misinterpreted. There are methodological issues to consider in assessing data availability and quality, and in deciding which countries to compare. Decisions about the data used and the countries selected should be documented with adequate rationale to ensure the limitations and assumptions are clear and duly considered. These decisions can influence the differences observed between countries and the conclusions made. What this guide adds The guide is intended to encourage users of international health-related data to consider the complexities before comparing countries, and to assist them in interpreting the results of these comparisons. It presents examples to highlight the types of questions to ask when using health data in an international context. The checklist presented in the Appendix and summarised below is not exhaustive; furthermore, considering these questions may not be possible in all cases. Checklist for international comparisons of health Data quality Consistency—are the data defined consistently across countries? Methodology—do all countries use the same method to collect the data? Coverage—do the data cover similar parts of the population? Time period—do the data refer to the same time period? Choice of countries Comparability—are countries sufficiently similar to support comparison? Presentation and interpretation Presentation—are the data presented appropriately? Explanation—is the variation between countries adequately explained? Underlying differentials—are differences within countries considered? Context—can the data be used outside of the international comparison