Critics of the Affordable Care Act continue to insist that the American health care system, as presently constructed, is the best in the world. But most of the available evidence suggests otherwise. And now there's yet one more set of data making the same point.

It comes from a study supported by the Commonwealth Fund, which specializes in comparisons of health care across country. And it looks at a statistic called "Mortality Amenable to Health Care." As the name suggests, it measures preventable deaths, which is a pretty good proxy for the quality of a nation's health care system. And how did the U.S. rank among 16 high-income, industrialized nations? Last. Yes, you read that right. Last.

Here are the details:

 In “Variations in Amenable Mortality—Trends in 16 High Income Nations,” Ellen Nolte of RAND Europe and Martin McKee of the London School of Hygiene and Tropical Medicine analyzed deaths that occurred before age 75 from causes like treatable cancer, diabetes, childhood infections/respiratory diseases, and complications from surgeries. They found that an average 41 percent drop in death rates from ischemic heart disease was the primary driver of declining preventable deaths, and they estimate that if the U.S. could improve its preventable death rate to match that of the three best-performing countries—France, Australia, and Italy—84,000 fewer people would have died each year by the end of the period studied. ...

Nolte and McKee noted that while preventable death rates declined in all 16 countries, the rate of decline varied significantly. Ireland, which ranked last with the highest preventable death rate in 1997–98, improved 42 percent by 2006–07. As a result, Ireland narrowed the gap with France, the country with the lowest “amenable mortality,” with 55 preventable deaths per 100,000 people. France was followed closely by Australia (57 per 100,000), and Italy (60 per 100,000). The U.S. ranked last, with 96 preventable deaths per 100,000 in 2006–07, down from 120 in 1997–98. The United Kingdom, which like Ireland began the decade with preventable death rates higher than the United States, now has rates that are considerably lower (83 per 100,000), reflecting more rapid improvement.

According to the study’s authors, the United States’ poor performance and relatively slow improvement compared with other nations may be attributable to “the lack of universal coverage and high costs of care.”

As I've written in past discussions of such statistics on quality of health care, you don't want to put too much stock in any one of them. They're inevitably reflect inconsistent standards, subjectivity of measurement, and so on. But this particular statistic is probably a better measure of health care quality than, say, sheer life expectancy. More important, when so many statistics make the U.S. look so bad by comparison, it's hard to argue credibly that we have the world's greatest health care system -- and that a law designed to give more people insurance, while cutting costs through incentives for efficiency, will make it worse.

(Note: The Commonwealth Fund has underwritten some of my research on health care systems abroad.)