Extensive research into quality of care in different countries yields no conclusive findings that one system is better or worse than others. Quality does not necessarily vary with financing mechanisms; even countries with single-payer systems have variations in quality. Quality is not directly related to the amount spent on health care, since the highest-spending country (the United States) does not have measurably better outcomes. Investments in the quality measurement and reporting systems in all countries would substantially increase the opportunities to learn from cross-national comparisons.